Charak Samhita
अथहेत्वन्तरं- हेत्वन्तरंनामप्रकृतहेतौवाच्येयद्विकृतहेतुमाह ॥६३॥
॥ 42. Hetvantara (change in statement of cause)॥ Hetvantara is that where some imperfect reason (vikritahetu) is stated instead of perfect reason (prakritahetu).
english translation
athahetvantaraM- hetvantaraMnAmaprakRtahetauvAcyeyadvikRtahetumAha ॥63॥
hk transliteration by Sanscript