We all know that the word Hindu is a Persian word for the Sindu river and was later used to refer to the region to other side of the Sindu river as Hindustan which then became India. But this page says there are some people who try to justify the word "Hindu" was used by Rishis several thousand years ago by citing this verse:
Aaasindo Sindhu Paryantham Yasyabharatha Bhoomikah
Mathrubhuh Pithrubhoochaiva sah Vai Hindurithismrithaah
Rough Translation: Whoever considers the land of Bharatha Bhoomi between Sapta Sindu and the Indian Ocean as his or her motherland and fatherland is known as Hindu.
The above verse is said to be from Vishnu Purana, Padma Purana and the Bruhaspati Samhita.
Is the verse authentic or this verse just interpolation?