Natyashastra
विवधेन तु तत्कार्यो युग्मवृत्तेन चैव हि । न ह्यर्धसन्निपाते तु भवेदङ्गसमापनम् ॥ १८८॥
They are to be performed there with the Vivadha or the twofold Vṛtta, and the Aṅga will not come to a close in a half of the Sannipāta.
english translation
vivadhena tu tatkAryo yugmavRttena caiva hi । na hyardhasannipAte tu bhavedaGgasamApanam ॥ 188॥
hk transliteration by Sanscript