Praṇava vityā parimaḷam, eṉṉum, Ōṅkāra viḷakkam : nāṇūṟu Vētap piramāṇaṅkaḷuṭaṉ - Aruṇakiri Mutaliyār (SAMP early 20th-century Indian books project, 1920)
Exposition of the mystic syllable "Om"