The fifth chapter holds the irregular verbs.
Some of these verbs are indicated as verb-endings (e.g. ~tener). This means that all tener-verbs (e.g. mantener, obtener) are built following the conjugation rules for the tener-verb.
Chapter 1: General Information
Chapter 2: The regular verbs
Chapter 3: Vocal-dependent, irregular verbs
Chapter 4: The irregular verb-endings
Chapter 5: The irregular verbs
Chapter 6: Verbs with irregular Participio Pasado
Chapter 7: Appendix