Portal:The Library of Congress, Sanskrit and Prakrit (2012)
“ Notes Only the vowel forms that appear at the beginning of a syllable are listed; the forms used for vowels following a consonant can be found in grammars; no distinction between the two is made in transliteration. The vowel a is implicit after all consonants and consonant clusters and is supplied in transliteration, with the following exceptions: a) when another vowel is indicated by its appropriate sign; and b) when the absence of any vowel is indicated by the subscript sign ( ◌् ) called halanta or virāma. ”
