Alexander Ruf, Andreas Mühling, Peter Hubwieser: Scratch vs. Karel: impact on learning outcomes and motivation. In: Proceedings of the 9th Workshop in Primary and Secondary Computing Education on – WiPSCE '14. ACM Press, Berlin, Germany 2014, ISBN 978-1-4503-3250-7, S.50–59, doi:10.1145/2670757.2670772 (acm.org [abgerufen am 2. Dezember 2021]).
Alexander Ruf, Andreas Mühling, Peter Hubwieser: Scratch vs. Karel: impact on learning outcomes and motivation. In: Proceedings of the 9th Workshop in Primary and Secondary Computing Education on – WiPSCE '14. ACM Press, Berlin, Germany 2014, ISBN 978-1-4503-3250-7, S.50–59, doi:10.1145/2670757.2670772 (acm.org [abgerufen am 2. Dezember 2021]).