Brihat Samhita
त्रिंशत्यधिका राहोस्ते तामसकीलका इति ख्याताः । रविशशिगा दृश्यन्ते तेषां फलं अर्कचारोक्तम् ॥ ११-२२ ॥
The Ketus that appear as spots in the solar and lunar discs are 33 in number. They are named as Tāmasa and Kīlaka Ketus. They are the sons of Rāhu. Their effects have been stated in the chapter on the Sun (vide stanza 7, Ch. 3.)
english translation
triMzatyadhikA rAhoste tAmasakIlakA iti khyAtAH । ravizazigA dRzyante teSAM phalaM arkacAroktam ॥ 11-22 ॥
hk transliteration by Sanscript