Cita APA (7th ed.)

Nakagawa, K., Yamada, K., Tsurue, T., Takeda, S., Ishizaki, K., Quilao, T., . . . Herrera, A. (1997). Characterization of coal ash. Philippine Engineering Journal.

Cita Chicago (17th ed.)

Nakagawa, K., et al. "Characterization of Coal Ash." Philippine Engineering Journal 1997.

Cita MLA (9th ed.)

Nakagawa, K., et al. "Characterization of Coal Ash." Philippine Engineering Journal, 1997.