De Leon, H. S., & De Leon, H. M. (2000). Comments and cases on obligations and contracts (3rd ed.). Rex Book Store.
Lua i Stíl Chicago (17ú heag.)De Leon, Hector S., agus Hector M. De Leon. Comments and Cases on Obligations and Contracts. 3rd ed. Manila: Rex Book Store, 2000.
Lua MLA (9ú heag.)De Leon, Hector S., agus Hector M. De Leon. Comments and Cases on Obligations and Contracts. 3rd ed. Rex Book Store, 2000.
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