http://www.teach-ict.com/2016/A_Level_Computing/OCR_H446/1_1_characteristics_components/111_architecture/von_neumann/miniweb/pg3.php
https://en.wikibooks.org/wiki/A-level_Computing/AQA/Paper_2/Fundamentals_of_computer_organisation_and_architecture/The_stored_program_concept
http://cse4k12.org/how_computers_work/