Natyashastra
मुखप्रतिमुखोपेता ह्यवकृष्टा विधीयते । वैहायसान्ताहरणे स्थितायां सम्प्रकीर्त्यते ॥ १२॥
The Avakṛṣṭā Dhruvā is defined as having the Mukha and Pratimukha; and in the Sthitā Dhruvā are included the Vaihāyasa and the Antāharaṇa.
english translation
mukhapratimukhopetA hyavakRSTA vidhIyate । vaihAyasAntAharaNe sthitAyAM samprakIrtyate ॥ 12॥
hk transliteration by Sanscript