Cita APA (7th ed.)

Villanueva, R., & Dulce, L. (2012). Langis at kalikasan. DZUP.

Cita Chicago (17th ed.)

Villanueva, Raymund, i Leon Dulce. Langis at Kalikasan. Quezon City: DZUP, 2012.

Cita MLA (9th ed.)

Villanueva, Raymund, i Leon Dulce. Langis at Kalikasan. DZUP, 2012.