Apple oop paper

https://stackoverflow.com/questions/5484278/in-oop-if-objects-send-each-other-messages-wont-there-be-easily-an-infinite-l/5509529

https://salvadorperni.ch/Dev/objective_c/Fichiers/OOP_ObjC.pdf or  https://web.archive.org/web/20181226131233/https://salvadorperni.ch/Dev/objective_c/Fichiers/OOP_ObjC.pdf

links
Category mistake

oop