Electronic/World Wide Web>Blog:  Bentley, Nick (February 2019), Variable Ratio Schedule for Getting Kids Addicted to Board Games, Retrieved on 2019-11-09

Source Material [www.nickbentley.games]

Audiovisual Media>Audio Recording:  , Geoff (16 September 2018), GameTek Classic 183 - Input Output Randomness, Retrieved on 2018-11-02

Source Material [ludology.libsyn.com]

Books, Brochures, and Chapters>Book:  Holt, Rinehart, Winston (1975), Games of the World: How to Make Them, How to Play Them, How They Came to Be, Plenary Publications International, New York, Retrieved on 2018-07-27