 Dignāga wrote three works pertaining to reasoning and argument. Unfortunately, in each case, the original Sanskrit text is not available. One, the Nyāya-mukha (Introduction to logic), is extant in Chinese translation and a Sanskrit manuscript is known to exist in Tibet. The remaining two are extant only in Tibetan translation: Hetu-cakra-ḍamaru (The drum wheel of reason) and his magnum opus, Pramāṇa-samuccaya (Compendium on epistemic means of cognition), four of whose six chapters are devoted to inference or argument.