University of the Philippines, Learning Resource Center, Elec, B. M., Lerios, M. C., Belarmino, M. C., Velasquez, G. A., & Panopio, R. G. (1999). Personalized System of Instruction (PSI) for college algebra. University of the Philippines, Learning Resource Center.
Chicago-viite (17. p.)University of the Philippines, Learning Resource Center, Bernarda M. Elec, Marcelina C. Lerios, Myrna C. Belarmino, Gemma A. Velasquez, ja Rolando G. Panopio. Personalized System of Instruction (PSI) for College Algebra. Quezon City: University of the Philippines, Learning Resource Center, 1999.
MLA-viite (9. p.)University of the Philippines, Learning Resource Center, et al. Personalized System of Instruction (PSI) for College Algebra. University of the Philippines, Learning Resource Center, 1999.