Zelda's Axiom: Whenever somebody tells you about "the five ancient talismans" or "the nine legendary crystals" or whatever, you can be quite confident that Saving the World will require you to go out and find every last one of them.
B. Okreša Đurić, and M. Konecki. Central European Conference on Information and Intelligent Systems, page 185--190. Varazdin, HR, University of Zagreb, Faculty of Organization and Informatics Varazdin, (2015)