@inproceedings{ITiCSE-2014-BerryK,
	author        = "Michael Berry and Michael Kölling",
	booktitle     = "{Proceedings of the 19th Conference on Innovation and Technology in Computer Science Education}",
	doi           = "10.1145/2591708.2591721",
	isbn          = "978-1-4503-2833-3",
	pages         = "21--26",
	publisher     = "{ACM}",
	title         = "{The state of play: a notional machine for learning programming}",
	year          = 2014,
}