Natyashastra
विवधं वापि वृत्तं वा तस्यादौ परिकीर्तिता । आकारवृत्तपरुषोऽत्र स्याच्चतुष्कं त्रिकमेव ॥ २९८॥
Whether it is a Vivadha or a Vṛtta, it is described at the beginning. Here, the Ākāra Vṛtta, being firm, will be of four Kalās or three.
english translation
vivadhaM vApi vRttaM vA tasyAdau parikIrtitA । AkAravRttaparuSo'tra syAccatuSkaM trikameva ॥ 298॥
hk transliteration by Sanscript