Natyashastra
चतुरस्रस्तथा त्र्यस्रो मिश्रश्चान्तः प्रकीर्तितः । उवेणकस्य संहारो द्व्यङ्ग एकङ्ग एव च ॥ २०४॥
The many limbs of the Ullopyaka, both separately and in combination, are to be known as of three kinds — Caturasra (fourfold), Tryasra (threefold), and Miśra (mixed). The Saṃhāra (concluding section) of the Oveṇaka, however, consists of either two limbs or one.
english translation
caturasrastathA tryasro mizrazcAntaH prakIrtitaH । uveNakasya saMhAro dvyaGga ekaGga eva ca ॥ 204॥
hk transliteration by Sanscript