Seishi Karashima, "On Amitābha, Amitāyu(s), Sukhāvatī and the Amitābhavyūha"

"The author demonstrates that the form Amitābha (“Limitless Light”) was original and only later did it evolve into Amitāyus (“Limitless Life”). The original form of the transliteration 阿彌陀 (ʔâ mjie dâ) might have been the Middle Indic form Amitāha / *Amidāha (pronounced as *Amidā’a in Gāndhārī) of Amitābha. The title of the sutra, Sukhāvatīvyūha, which appears only in the Sanskrit manuscripts, was added later as a subtitle, and it originally had the title of Amitābhavyūha, Amitābhasya vyūha or the like, and the Chinese translations could have also been entitled as such.