De Leon, H. S., & De Leon, H. M. J. (2019). Comments and cases on obligations and contracts (Seventh edition.). Rex Book Store.
Lua i Stíl Chicago (17ú heag.)De Leon, Hector S., agus Hector M. Jr De Leon. Comments and Cases on Obligations and Contracts. Seventh edition. Manila: Rex Book Store, 2019.
Lua MLA (8ú heag.)De Leon, Hector S., agus Hector M. Jr De Leon. Comments and Cases on Obligations and Contracts. Seventh edition. Rex Book Store, 2019.
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