Natyashastra
एवमेतद्बुधैर्ज्ञेयं माणं तालप्रमाणतः । तद्गाथापाणिकादीनां सप्तरूपं प्रकीर्तितम् ॥ ३२९॥
Thus, this measure should be understood by the learned according to the standard of rhythm (tāla). The seven forms, beginning with gāthā and pāṇika, are declared in this manner.
english translation
evametadbudhairjJeyaM mANaM tAlapramANataH । tadgAthApANikAdInAM saptarUpaM prakIrtitam ॥ 329॥
hk transliteration by Sanscript