Shiva Purana
अनायुषायाः पुत्राश्च पंचाशच्च महाबलाः ॥ अभवन्बलवृक्षौ च विक्षरोऽथ बृहंस्तथा ॥ ४९ ॥
Anāyuṣā’s sons were fifty. They were very strong. The chief amongst them were Bala, Vṛtta, Vikṣara and Bṛhan.
english translation
anAyuSAyAH putrAzca paMcAzacca mahAbalAH ॥ abhavanbalavRkSau ca vikSaro'tha bRhaMstathA ॥ 49 ॥
hk transliteration by Sanscript