APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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