Book - Previous books or propositions upon which it depends

I    - (independent)
II   - I
III  - I; II.5,6
IV   - I; II.11; III
V    - (independent)
VI   - I; III.27,31; V
VII  - (independent)
VIII - V.Def.; VII
IX   - II.3,4; VII; VIII
X    - I.44,47; II; III.31; V; VI; VII.4,11,26; IX.1,24,26
XI   - I; III.31; IV.1; V; VI
XII  - I; III; IV.6,7; V; VI; X.1; XI
XIII - I; II.4; III; IV; V; VI; X; XI