APA (7th ed.) Citation

De Leon, H. S. (1989). Textbook on the new Philippine constitution (1989 ed.). Rex Book Store.

Chicago Style (17th ed.) Citation

De Leon, Hector S. Textbook on the New Philippine Constitution. 1989 ed. Quezon City, Manila: Rex Book Store, 1989.

MLA (9th ed.) Citation

De Leon, Hector S. Textbook on the New Philippine Constitution. 1989 ed. Rex Book Store, 1989.