Book IV. Obligations and contracts -- Title I. Obligations -- Chapter 1-3 -- Chapter 1. Concept and elements -- Chapter 2. Sources of obligations -- Chapter 3. Civil and natural obligations -- Chapter 4. Real and personal obligations -- Chapter 5. Breach of obligation -- Chapter 6. Pure and conditional obligations -- Chapter 7. Obligations with the term or period -- Chapter 8. Alternative and facultative obligations -- Chapter 9. Joint and solidarity obligations -- Chapter 10. Divisible and invisible obligations -- Chapter 11. Obligations with a penal clause -- Chapter 4. Extinguishment of obligations general provisions -- Chapter 12. Payment or performance -- Chapter 13. Loss of prestation -- Chapter 14. Condonation and confusion -- Chapter 15. Compensation -- Chapter 16. Novation -- Title II. Contracts -- Chapter 1-5 -- Chapter 17. Concepts, elements and characteristics -- Chapter 18. Essentials of requisites of contracts -- Chapter 19. Form, reformation and interpretation of contracts -- Chapter 6-9 -- Chapter 20. Recissible contracts -- Chapter 21. Voidable contracts -- Chapter 22. Unenforceable contracts -- Chapter 23. Void or inexistent contracts.

Rabuya, E. (2019). Obligation and contract (2019 ed). Rex Book Store