Natyashastra
पञ्चमे च महानागाः शेषवासुकितक्षकाः । एवं विघ्नविनाशाय स्थापिता जर्जरे सुराः ॥ ९४॥
In the fifth place, the great serpents, Shesha, Vasuki, and Takshaka, were positioned. Thus, the gods were established to destroy the obstacles.
english translation
paJcame ca mahAnAgAH zeSavAsukitakSakAH । evaM vighnavinAzAya sthApitA jarjare surAH ॥ 94॥
hk transliteration by Sanscript