Thirty Endangered Languages in the Philippines . Thomas N. Headland (2003) · Work Papers of the Summer Institute of Linguistics, University of North Dakota Session. 47

The Casiguran Dumagats Today and in 1936 ( pp. 245-257 ) . Thomas N. Headland (1975) · Philippine Quarterly of Culture and Society. 3

Why Foragers do not Become Farmers: A historical study of a changing ecosystem and its effect on a Negrito hunter-gatherer group in the Philippines . Thomas N. Headland (1986) ·

A Dumagat (Casiguran) - English dictionary . Thomas N. Headland and Janet D. Headland (1974) · Pacific Linguistics: Series C · Vol. 28 · Canberra: Research School of Pacific and Asian Studies, Australian National University

Grammatical Sketch of Casiguran Dumagat ( pp. 1-54 ) . Thomas N. Headland and Alan Healey (1974) · In Papers in Philippine Linguistics 6 Pacific Linguistics: Series A · Vol. 43 ·

A Dumugat (Casiguran) - English Dictionary . Headland, Thomas N. and Headland, Janet D. (1974) · Pacific Linguistics, Series C · Vol. 28 · Australian National University