Sanskrit Wikisource: तैत्तिरीयोपनिषदत् (3 pages; revision ids 415078, 417713, 404064, full list in content/corpus/wikisource cache) — Vallīs numbered śikṣā 1, brahmānanda 2, bhṛgu 3; units are anuvākas in the order of the page's headings (vallī.anuvāka).
Sanskrit Wikisource (sa.wikisource.org): the texts are public domain; page markup CC BY-SA 4.0. Devanagari as given on the page; IAST generated mechanically.