ISKCON is a part of Chaitanya Vaishnavism whose theology is mainly based on Bhagavata purana.
We will consider works of Jiva Goswami mainly(contemporary of Chaitanya) & at times Baladeva Vidyabhusana as they are the Vedanta acharyas of Gaudiya Vaishnavism. And then see if the usage of ISKCON is justified.
How they go about in search of Absolute Truth is discussed in Tattva Sandarbha. In brief:
The search for Absolute Truth is to be done through Vedas. (Here Purva Mimamsa, Vedanata, and other darshanas are brought in and analysed)
But, Vedas are very difficult to grasp and people have interpreted differently.
Puranas and Itihasas are established as the 5th Veda.
Then he says:
Since the words of the Vedas are now difficult to access and difficult to
understand, and since sages who explain the texts mutually disagree on the
meaning, the words of Itihāsas and Purāṇas, which explain the meaning of
the Vedas and which are another form of the Vedas, should be discussed.
Those statements in the Vedas which cannot be understood can be
understood by seeing the Purāṇas and Itihāsas. That fact establishes these
scriptures as proof in Kali-yuga.
itihāsa-purāṇābhyāṁ vedaṁ samupabṛṁhayet
One should clarify the meaning of the Vedas by the Itihāsas and Purāṇas. Mahābhārata 1.1.267
Special significance of Puranas:
vedārthād adhikaṁ manye purāṇārthaṁ varānane |
vedāḥ pratiṣṭhitāḥ sarve purāṇe nātra saṁśayaḥ ||
purāṇam anyathā kṛtvā tiryag-yonim avāpnuyāt |
sudānto’pi suśānto’pi na gatiṁ kvacid āpnuyāt ||
O beautiful faced woman! I consider the meaning of the Purāṇas greater than the meaning of the Vedas. The Vedas are established in all the Purāṇas without doubt. If one disrespects the Purāṇas one attains an animal birth. Though controlling the senses and mind, one never attains the spiritual goal.
vedavan niścalaṁ manye purāṇārthaṁ dvijottamāḥ |
vedāḥ pratiṣṭhitāḥ sarve purāṇe nātra saṁśayaḥ ||
bibhety alpa-śrutād vedo mām ayaṁ cālayiṣyati |
itihāsa-purāṇais tu niścalo’yaṁ kṛtaḥ purā ||
yan na dṛṣṭaṁ hi vedeṣu tad dṛṣṭaṁ smṛtiṣu dvijāḥ |
ubhayor yan na dṛṣṭaṁ hi tat purāṇaiḥ pragīyate ||
yo veda caturo vedān sāṅgopaniṣado dvijāḥ |
purāṇaṁ naiva jānāti na ca sa syād vicakṣaṇaḥ ||
O best of the brāhmaṇas! I consider the meaning of the Purāṇas to be fixed like the Vedas. The Vedas are established in all the Purāṇas without doubt. The Vedas were afraid of people with little knowledge, thinking they would distort the meaning. The Vedas have been established by the Itihāsas and Purāṇas in ancient times. What is not seen in the Vedas is seen in the smṛtis. What is not seen in the smṛtis is described in the Purāṇas. The clever person who knows the Vedas and Upaniṣads but does not know the Purāṇas is not knowledgeable.
Skanda Purāṇa, Prabhāsa-khaṇda 2.90-93
Next, he says:
Though the Purāṇas are established as authority because they do not leave the
meaning unsettled, those who are less intelligent still find the meaning of the
Purāṇas difficult to grasp, since the Purāṇas are unavailable in complete form
and since they instill faith in worshipping various devatās.
Then he uses Matsya purana classification and says Sattvita puranas(that glorify hari) are to be focussed.
Even accepting the superiority of sattvika Purāṇas, how can one solve
conflicting ideas concerning the ultimate spiritual goal made by logicians using various devices?[the highest goal is defined as having qualities, having no qualities, composed of knowledge only and completely unconscious by various types of crooked logic] It is said that, since the Lord in the form of Vyāsa wrote the Brahma-sūtras for explaining the meaning of all the Vedas and Purāṇas, by consulting it one can discern the meaning of all scriptures. But it is not understood by followers of various other sages who wrote other sūtras. Some will explain opposite meaning in the sūtras which are sparse in syllables and extremely deep in meaning. What is the solution?
The problem will be solved if there is one apauruṣeya, well-accepted, complete
scripture manifest on earth, which explains Brahma-sūtras and which contains
the essential meaning of all the Vedas, Itihāsas and Purāṇas.
Yes, you have brought us to mind 'Srimad Bhagavatam'..
Some may think that the Purāṇas’ authority depends on the Vedas. That
possibility is rejected for Bhāgavatam, and is stated in Bhāgavatam itself: it is
the highest śruti.
kathaṁ vā pāṇḍaveyasya rājarṣer muninā saha |
saṁvādaḥ samabhūt tāta yatraiṣā sātvatī śrutiḥ ||
How did the conversation of Parīkṣit with Śukadeva arise, through which this Vaiṣṇava śruti appeared? SB 1.4.7
Thus, he says we focus our attention on Bhagavatam in our search for Absolute Truth and other apparently contradictory
statement in other scriptures meaning will be discerned with the help of Bhagavatam.
And in Bhagavata purana the word bhagavan has great significance than just conventional usage in Sanskrit language.
The key to the Gaudiya understanding of Bhagavan lies in a verse found
in the second chapter of the first book of the BhAgavata:
vadanti tat tattva-vidas tattva| yaj jñAnam advayam
brahmeti paramAtmeti bhagavan iti sabdyate
Knowers of reality declare that reality to be nondual consciousness,
called “Brahman,” “Paramatma,” and “Bhagavan.”
Here Bhagavan is referring to the Absolute Truth. It has greater meaning than a normal usage.
These two answers also provide about significance of Bhagavan,
Definition of Bhagavan as per Vishnu Purana
Which scripture describes six kalyana gunas (auspicious attributes) of Vishnu?
This text is so often cited and explained in Gaudiya literature that some
authors credit the entire Caitanya Vaisnava theory of the threefold Godhead
to this verse alone. Although the theory, and especially the concept of
Bhagavan, are in fact based on a much broader understanding of the
BhAgavata PurAWa,(This is evident from the Bhagavat-sandarbha, wherein Jiva assembles and explains a wide
variety of verses from the BhAgavata to establish the concept of the threefold Godhead and the supremacy of Bhagavan. A similar attempt is made in section 105 of ParamAtma-sandarbha, wherein the six indicators of meaning (tAtparya-lingas) are delineated using verses from various parts of the BhAgavata) the verse nevertheless occupies a crucial place in Gaudiya theology for several reasons.
First, if Jiva is to establish the concept of Bhagavan in the technical,
Caitanyite sense of the term, he must first of all introduce a distinction
between Bhagavan and other commonplace conceptions of Godhead, such
as the inner controller (antaryAmC) and supersoul (paramAtmA). By juxtaposing
three different names for God in a single line (Brahman, Paramatma,
and Bhagavan), the Bhagavata verse allows exegetical space for such a distinction to be made. After all why would the PurAna mention these three
names and claim that they are “nondual” if there were no reason to think
them separate in the first place?
Thus, by introducing multiplicity in the Divine, the “vadanti” verse allows
Gaudiya theologians to develop and lay claim to the concept of Bhagavan.
The verse is equally important, however, for just the opposite reason: Once
the threefold scheme has been developed, the verse protects Gaudiya commentators from accusations of dividing the Absolute, since it clearly states
that the three are in fact one nondual reality. The first line of the verse is as useful to Gaudiya Vaisnava writers as the second, for by identifying the
nondual reality with Krisha, they can claim Krishna to be the ultimate referent
of all three names: Brahman, Paramatma, and Bhagavan. This allows them
to direct even monistically inclined Upanisadic passages toward Bhagavan.
In his instructions to Sanatana Gosvami at Kasi, Caitanya explains the
implications of the “vadanti” verse:
The word “Brahman” refers to Svayam Bhagavan, who is one consciousness without a second, and without whom there is nothing else. “Knowers of reality declare that reality to be nondual consciousness, called ‘Brahman,’ ‘Paramatma,’ and ‘Bhagavan.’” That nondual reality is Krsna, Bhagavan himself. He exists in all three phases of time (past, present, and future). This is evident from the scriptures. . . . The word “AtmA” refers to Krsna. His nature is greatness [b[hattva]. He is all pervading, the witness of everything, and the supreme form . . . Although the words “Brahman” and “AtmA” refer to Krishna, by conventional usage they refer to the Undifferentiated [nirvisesa] and the Inner Controller [antaryAmi], respectively.
The title “svayam bhagavan,” (“Bhagavan himself,” or “directly Bhagavan”) is used exclusively to designate Krishna. It is drawn from the famous statement of the Bhagavata:
“ete camsa-kalah pumsas krsnas tu bhagavan svayam.
“All these (avatAras) are portions or portions of portions of the Lord, but Krishna is Bhagavan himself” (1.3.28). This half-verse appears at the end of the list of twenty-two prominent incarnations (avatAras), and is on par with the “vadanti” verse as a pace-setting text in Chaitanya Vaisnava theology. It forms the basis for the complex classification of Krishna’s forms and manifestations found in the Laghu-bhAgavatAmrta of Rupa Gosvami, CaitanyacaritAmrita, and Krisha-sandarbha.
Thus, we can see that absolute truth is referred by word bhagavan.
The absolute truth is described in first verse of bhagavata as well.
O my Lord, Śrī Kṛṣṇa, son of Vasudeva, O all-pervading Personality of Godhead, I offer my respectful obeisances unto You. I meditate upon Lord Śrī Kṛṣṇa because He is the Absolute Truth and the primeval cause of all causes of the creation, sustenance and destruction of the manifested universes. He is directly and indirectly conscious of all manifestations, and He is independent because there is no other cause beyond Him. It is He only who first imparted the Vedic knowledge unto the heart of Brahmājī, the original living being. By Him even the great sages and demigods are placed into illusion, as one is bewildered by the illusory representations of water seen in fire, or land seen on water. Only because of Him do the material universes, temporarily manifested by the reactions of the three modes of nature, appear factual, although they are unreal. I therefore meditate upon Him, Lord Śrī Kṛṣṇa, who is eternally existent in the transcendental abode, which is forever free from the illusory representations of the material world. I meditate upon Him, for He is the Absolute Truth.
Thus considering overall context of Bhagavata and various definitions found in Vishnu Purana, the special usage of word bhagavan is explained in Bhagavat Sandarbha.
tad eva sac-cid-anandaika-repas
svarepa-bhetacintya-vicitrananta-uakti-yukto dharmatva eva dharmitva
nirbhedatva eva nana-bhedavattvam arepitva eva repitva vyapakatva eva
madhyamatva satyam evety adi-paraspara-viruddhanantaguwa- nidhis
ananta-prapañca-vyañjita-svabhasa-uakti-guwo bhagavan iti.
He who is the very form of existence, consciousness, and bliss; who possesses inconceivable, multifarious, and unlimited energies that are of his own nature; who is the ocean of unlimited, mutually contradictory qualities, such that in him both the attribute and the possessor of attributes, the lack of differences and varieties of differences, formlessness and form, pervasiveness and centrality [madhyamatva]—all are true; whose beautiful form is distinct from both gross and subtle entities, self-luminous, and consisting entirely of his own nature; who has unlimited such forms that are manifested by his chief form called Bhagavan; whose left side is beautified by Lak1mc—the manifestation of his personal energy, suitable to his own form; who resides in his own abode, along with his associates, who are furnished with a form that is a special manifestation of his own splendor; who astonishes the hosts of AtmArAmas (those who take pleasure in the self ) by his wonderful qualities, pastimes, etc., which are characterized by the play of his personal energy; whose own generic brilliance is manifested in the form of the reality of Brahman; who is the sole shelter and life of his marginal energy, called the living entities [ jivas]; whose mere reflected energy are the modes of nature [guNas], visible in the unlimited phenomenal world— he is Bhagavan.
But, one may say that Bhagavan is used for Shukracharya, Shiva also in Bhagavatam and he is glorified as supreme.
Yes, but they are very weaker statements as shown by the below sutra.
Where there is contradiction of one scriptural statement with another, one must consider which is stronger. Strength is based on the scriptural source and the source of the statement
śruti-liṅga-vākya-prakaraṇa-sthāna-samākhyānāṁ samavāye pāra-daurbalyam artha-viprakarṣāt
Where there is a combination of literal meaning, interpretive meaning, altering the syntax, referring to other texts, philosophical stances, and etymological meaning, the later statements are considered progressively weaker in authority, because of the possibility of their producing contrary meaning. Jaimini-sūtra 3.3.14
Śruti means direct meaning, liṅga means suggested meaning, vākya means interpretation through taking the phrases as a whole, prakriyā or prakaraṇa means intentionally taking a word out of context. Sthānam means interpretation according to a philosophical stance and samākhyā means etymology.
The statements where Shiva is glorified as para brahman in 7th chapter of 8th Canto or identified as Bhagavan in 12th Canto by Markandeya.
na te giri-trākhila-loka-pālaviriñca-
jyotiḥ paraṁ yatra rajas tamaś ca
sattvaṁ na yad brahma nirasta-bhedam
O protector of mountains (Śiva)! Your supreme light known as Brahman
which is devoid of rajas, tamas and sattva and devoid of distinctions is not
known by the devatās, Viṣṇu or Indra. SB 8.7.31
But Śiva is not supreme. The contrary statements follow this verse. Such statements are made according to the Vedic reasoning that “the devatās should increase in strength by praising them with greatness.” This praise is given so that Śiva will destroy the kālakūtā poison.
prīte harau bhagavati prīye 'haṁ sacarācaraḥ: when the Lord is pleased, I (Śiva) am also pleased, along with all other living creatures. (SB 8.7.40)
Therefore, direct words of Suta/Suka are higher in importance, and other statements should follow that to give proper meaning.
Understanding this distinction, identifying Śiva or any other God with this form is criticized:
athāpi yat-pāda-nakhāvasṛṣṭaṁ jagad viriñcopahṛtārhaṇāmbhaḥ |
seśaṁ punāty anyatamo mukundāt ko nāma loke bhagavat-padārthaḥ ||
Who can be called by the name Bhagavān except Mukunda whose toe-nail water purifies the universe along with Śiva and becomes arghya for Brahmā? SB 1.18.21
Suta speaks the verse..
Another place where it is clearly distinguished is in 89th chapter of 10th Canto :
Text 1: Śukadeva Gosvāmī said: Once, O King, as a group of sages were performing a Vedic sacrifice on the banks of the Sarasvatī River, a controversy arose among them as to which of the three chief deities is supreme.
Texts 14-17: Amazed upon hearing Bhṛgu’s account, the sages were freed from all doubts and became convinced that Viṣṇu is the greatest Lord. From Him come peace; fearlessness; the essential principles of religion; detachment with knowledge; the eightfold powers of mystic yoga; and His glorification, which cleanses the mind of all impurities. He is known as the supreme destination for those who are peaceful and equipoised — the selfless, wise saints who have given up all violence. His most dear form is that of pure goodness, and the brāhmaṇas are His worshipable deities. Persons of keen intellect who have attained spiritual peace worship Him without selfish motives.
Text 18: The Lord expands into three kinds of manifest beings — the Rākṣasas, the demons and the devatas— all of whom are created by the Lord’s material energy and conditioned by her modes. But among these three modes, it is the mode of goodness which is the means of attaining life’s final success.
Text 19: Śukadeva Gosvāmī said: The learned brāhmaṇas living along the river Sarasvatī came to this conclusion in order to dispel the doubts of all people. Thereafter they rendered devotional service to the Supreme Lord’s lotus feet and attained His abode.
This and the following story is narrated at the end of 10th Canto just to state the position of Vishnu and then Krishna's svayam bhagavan position.
And there are many other direct statements supporting the same.
How they deal with other statements from Vedas, Upanishads that may have seemingly contradictory meanings?
Of course, in line with Bhagavatam.
How they deal with Vedic statements glorifying others is not much focussed in Gaudiya Vaishnavism.
However, we get pointers...
In Vedanta Syamantaka of Baladeva Vidyabhusana...
Then someone may again protest: In Drona Parva, Vyasa glorified Lord
Siva with a hundred prayers. He said Lord Siva is the cause of all causes.
To this I reply: His prayers were in truth addressed to Lord Visnu, the
Supersoul in Lord Siva's heart. This must be so, for there cannot be two ParaBrahmans, and no one can be equal to the Para Brahman.
In this way the supreme position of Lord Visnu is proved. One should not be bewildered by reading in some Puranas some statements that Brahma or other
devatas have the highest supremacy. Those statements are Puranas in the modes of passion or ignorance, and therefore those statements
should be rejected.
In Govinda Bhasya of Baladeva Vidyabhusana..
Visaya: Someone may object: “Many passages in the scriptures do not support
your conclusion at all.” This adhikarana is written to dispel this doubt.
The Svetasvatara Upanisad explains:
ksaram pradhanam amrtaksarah harah
“Material nature is in constant flux and the Supreme, Lord Hara is eternal and unchanging.” 
eko rudro na dvitiyaya tasthuh
“Lord Rudra is the Supreme. He has no rival.” [3.2]
yo devanam prabhavas codbhavas ca visvadhiko rudrah sivo maharsih
“Lord Siva, who is known as Rudra, is the omniscient ruler of the universe. He is he father of all the demigods. He gives the demigods all their powers and
yada tamas tan na diva na ratrir na san na casac chiva eva kevalah
“When the final darkness comes and there is no longer day or night, when there
is no longer being and non-being, then only Lord Siva exists.” [4.18]
The scriptures also explain:
pradhanad idam utpannam pradhanam adhigacchati pradhane layam abhyeti na
hy anyat karanam matam
“From pradhana this material world was born. This world knows only
pradhana. This world merges into pradhana at the time of annihilation. Nothing
else is the cause of this world.”
jivad bhavanti bhutani jive tisthanty acancalah jive ca layam icchanti na jivat
“From the jiva all the elements of this world have come. In the jiva they rest
without moving, and they finally merge into the jiva. Nothing else is the cause of
Samsaya: Should Hara and the other names given in these quotes be understood
in their ordinary senses, as names of Lord Siva, pradhana, and jiva, or should
they all be understood to be names of the Supreme Brahman?
Purvapaksa: The names should all be understood in their ordinary senses, as
names of Lord Siva, pradhana, and jiva.
Siddhanta: The conclusion follows.
etena sarve vyakhyata vyakhyatah
etena - in this way; sarve - all; vyakhyatah - explained; vyakhyatah - explained.
All [words in the scriptures] should be interpreted to agree with the
explanation [that the Supreme Brahman is the original cause].
In this sutra the word etena means “according to the explanations already
given,” sarve means “Hara and the other names,” and vyakhyatah means “should
be understood to be names of the Supreme Brahman because all names are
originally names of the Supreme Brahman.”
The Bhālvaveya-śruti explains:
nāmāni viśvāni na santi loke
yad āvirāsīt puruṣasya sarvam
nāmāni sarvāṇi yam āviśanti
taṁ vai viṣṇuṁ paramam udāharanti
“The names of this world are not different from Him. All names in this world are names of the Supreme Personality of Godhead. All names refer to Him, Lord Viṣṇu, whom the wise declare is the Supreme Personality of Godhead.”
This is the rule that should be followed: When the ordinary sense of these names does not contradict the essential teaching of the Vedas, the ordinary meaning should be accepted. When the ordinary sense of these names does contradict the teaching of the Vedas, these names should be understood to be names of Lord Visnu.
Similarly there is Vedanta Sutra starting from 1.1.28 that deals with Indra being identified as Supreme Brahman in Kausitaki upanishad
Jiva Goswami also says in Bhakti Sandarbha:
rujaṁ drāvayate yasmād rudras tasmāj janārdanaḥ |
īśanād eva ceśāno mahā-devo mahattvataḥ ||
pibanti ye narā nākaṁ muktāḥ saṁsāra-sāgarāt |
tad-ādhāro yato viṣṇuḥ pinākīti tataḥ smṛtaḥ ||
śivaḥ sukhātmakatvena sarva-sarodhanād dharaḥ |
kṛtyātmakam imaṁ dehaṁ yato vaste pravartayan ||
kṛttivāsās tato devo viriñciś ca virecanāt |
bṛṁhaṇād brahma-nāmāsau aiśvaryād indra ucyate ||
evaṁ nānā-vidhaiḥ śabdair eka eva trivikramaḥ |
vedeṣu ca purāṇeṣu gīyate puruṣottamaḥ ||
Because he drives away pain Viṣṇu is called Rudra. Because he is the controller he is called Īśāna. Because he is the greatest he is called Mahādeva. He is called Pinākī because he is the support of persons who, liberated from the ocean of saṁsāra, enjoy (pi) the spiritual sky (nāka). He is called Śiva because he is the embodiment of happiness. He is called Hara because he destroys everything. He is called Kṛttivāsa because he lives in and operates the body which produces action (kṛtya). He is called Viriñci because he extends beyond. He is called Brahmā because he is expands. He is called Indra because he has power. Thus the one supreme Lord is glorified by various types of names in the Vedas and Purāṇas.
So, it is either name referring to Krishna or the actual glory is to the supersoul and thus Bhagavan Krishna depending on the context.
As Krishna says in Bhagavatam,
kiṁ vidhatte kim ācaṣṭe kim anūdya vikalpayet
ity asyā hṛdayaṁ loke nānyo mad veda kaścana
What do the Vedas instruct as action? What is the final meaning of the
Vedas? What alternatives do the Vedas raise? No one except me or my dear
devotee knows the intended meaning of the Vedas.
māṁ vidhatte ’bhidhatte māṁ vikalpyāpohyate tv aham
etāvān sarva-vedārthaḥ śabda āsthāya māṁ bhidām
The Vedas indicate bhakti as the action and indicate me as the meaning. I am the meaning of all the Vedas. I, as karma and jñāna, am proposed and rejected as alternatives. SB 11.21.42-43
As he also says in Gita,
I am situated in everyone’s heart. From Me come remembrance, knowledge
and forgetfulness. And I am also known by all the Vedas. I am the maker of
the Vedanta since I alone know the Vedas. BG 15.15
Baladeva Vidyabhusna comments:
Having shown how He alone enables the jivas to enjoy in the material world, the Lord now shows how He alone enables the jivas to get liberation. I alone, the Lord of all, holder of all powers, Krsna, am to be known by all the Vedas. The sruti says yo’sau sarvair vedair giyate: It is He who is praised by all the Vedas. (Gopala Tapani Upanisad) I am to be known indirectly through karma kanda
portion of the Vedas and directly through the jnana kanda portion of the Vedas.
“How is this to be understood?”
“I have produced the final conclusion (anta) of the Vedas, Vedanta Sutras, by taking the form of Badarayana. Thus the author of the vedanta says ta tu
samanvayat: Visnu is the subject of the Vedas because that is the meaning of all Vedic texts. (Vedanta Sutras 1.1.4)”
"But others will explain the meaning of the Vedas in a different way.”
“I alone am the knower of the Vedas (veda vit). The meaning which I have
determined by becoming Badarayana is the meaning of the Vedas. Any other
meaning is filled with error. Thus I alone (as Badarayana) am the producer of
liberation, since even by studying the Vedas there is misunderstanding about the identity of the Supreme Lord who bestows liberation.”
Therefore when bhagavan is used for any other sage or deva in Bhagavatam, it will not have the same meaning as used in Chaitanya Vaishnavite sense, it just means 'O glorious one' or something like that.
This may be the reason why ISKCON uses 'Supreme Personality of Godhead' when Krishna/Vishnu is referred as bhagavan, but normal sense of word when another deva/sage is referred as bhagavan. 'Supreme Personality of Godhead' gives the feeling of Supreme and Person with many charactersitics at the same time.
Thus, in Chaitanya Vaishavite sense, to make a distinction between Krishna/Vishnu and other devas, they may be using word 'demigod'. Probably translating as 'god' may give polytheistic conception in mind which they wanted to avoid. One of the meanings of demigod is a minor deity. It may not have that connotation in general. But this site allows use of mythology though it has negative connotation. All other devas are considered minor deities in Chaitanya Vaishnavism or Vaishnavism in general. Therefore, the usage properly conveys the Chaitanya Vaishnavite concepts and is in line with Vedanta teachings skipping technical discussions.
I referred ISKCON's translations in Hindi, they translate demigod as deva not as upadeva/apadeva. So users can give up their demiwordphobia :)
Ref 1: Chaitanya Vaishnava Vedanta, ROUTLEDGE HINDU STUDIES SERIES
Edited by: Gavin Flood
University of Stirling, Ravi M Gupta, Assistant Professor of Religion at Centre College,
Kentucky, USA and Associate Lecturer for the University of Wales Lampeter, Part I Chapter II CAITANYA VAISNAVA HERMENEUTICS.
Ref 2: Sat Sandarbhas of Jiva Goswami.
Ref 3: Govinda Bhasya of Baladeva Vidyabhusana
Ref 4: Vedanta Syamantaka of Baladeva Vidyabhusana.
Ref 5: Gita Bhusana of Baladeva Vidyabhusana