Gatbonton, E. B. (1985). Bastion de San Diego. Intramuros Administration, Ministry of Human Settlements.
Chicago-viite (17. p.)Gatbonton, Esperanza Bunag. Bastion De San Diego. Manila: Intramuros Administration, Ministry of Human Settlements, 1985.
MLA-viite (9. p.)Gatbonton, Esperanza Bunag. Bastion De San Diego. Intramuros Administration, Ministry of Human Settlements, 1985.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.