The question remains. The relation between: references, appropriations, and adaptations.

appropriate  
Use Appropriate in a sentence

ap·pro·pri·ate [adj. uh-proh-pree-it; v. uh-proh-pree-eyt] Show IPA
adjective
1.
suitable or fitting for a particular purpose, person, occasion, etc.: an appropriate example; an appropriate dress.
2.
belonging to or peculiar to a person; proper: Each played his appropriate part.
verb (used with object), ap·pro·pri·at·ed, ap·pro·pri·at·ing.
3.
to set apart, authorize, or legislate for some specific purpose or use: The legislature appropriated funds for the university.
4.
to take to or for oneself; take possession of.
5.
to take without permission or consent; seize; expropriate: He appropriated the trust funds for himself.
6.
to steal, especially to commit petty theft.

refer  
Use Refer in a sentence

re·fer [ri-fur] Show IPA
verb (used with object), re·ferred, re·fer·ring.
1.
to direct for information or anything required: He referred me to books on astrology.
2.
to direct the attention or thoughts of: The asterisk refers the reader to a footnote.
3.
to hand over or submit for information, consideration, decision, etc.: to refer the argument to arbitration.
4.
to assign to a class, period, etc.; regard as belonging or related.
5.
to have relation; relate; apply.