APA-viite (7. p.)

Herrera, A. (1999). Highly active absorbent for SO2 removal prepared from coal ash (Part 3). Philippine Engineering Journal.

Chicago-viite (17. p.)

Herrera, A.B. "Highly Active Absorbent for SO2 Removal Prepared from Coal Ash (Part 3)." Philippine Engineering Journal 1999.

MLA-viite (9. p.)

Herrera, A.B. "Highly Active Absorbent for SO2 Removal Prepared from Coal Ash (Part 3)." Philippine Engineering Journal, 1999.