Cita APA (7th ed.)

Sia, L. O. (1995). 21st century mathematics. Second year. Phoenix.

Cita Chicago (17th ed.)

Sia, Lucy O. 21st Century Mathematics. Second Year. Quezon City: Phoenix, 1995.

Cita MLA (9th ed.)

Sia, Lucy O. 21st Century Mathematics. Second Year. Phoenix, 1995.