Natyashastra
एवं कक्ष्याविभागस्तु धर्मी युक्तय एव च । विज्ञेया नाट्यतत्त्वज्ञैः प्रयोक्तव्याश्च तत्त्वतः ॥ ८५॥
Thus, the division of classes is to be understood by those knowledgeable in the principles of drama, and these divisions should be applied in practice according to the true nature of the art.
english translation
evaM kakSyAvibhAgastu dharmI yuktaya eva ca । vijJeyA nATyatattvajJaiH prayoktavyAzca tattvataH ॥ 85॥
hk transliteration by Sanscript