1 "Ficheiro:List_of_references_on_reciprocity;_(IA_list00ofreferenceslibrrich).pdf".

Ficheiro:List of references on reciprocity; (IA list00ofreferenceslibrrich).pdf

recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:List_of_references_on_reciprocity;_(IA_list00ofreferenceslibrrich).pdf...