Shuka, Ravana's aide, describes the individual strengths of the various commanders in the army of monkeys, mentioning their names one by one, in detail, in Yuddha Kanda of Srimad Ramayana.

[While describing Sri Hanuman][1], Shuka says that Sri Hanuman was the eldest son of Kesari.

>ज्येष्ठः केसरिणः पुत्रो वात आत्मज इति श्रुतः |<br>
>हनूमान् इति विख्यातो लन्घितो येन सागरः || ६-२८-१०
>
>This monkey, by whom the ocean was traversed, is the eldest son of Kesari. He is known as the son of wind-god and famously called as Hanuman.

Can anybody tell me how many sons did Kesari have, other than Sri Hanuman?

[1]: http://www.valmikiramayan.net/utf8/yuddha/sarga28/yuddhasans28.htm#Verse10