Waite, J. L., P. Curzon, W. Marsh, S. Sentance, and A. Hadwen-Bennett. “Abstraction in Action: K-5 teachers’ Uses of Levels of Abstraction, Particularly the Design Level, in Teaching Programming.”. International Journal of Computer Science Education in Schools, Vol. 2, no. 1, Jan. 2018, pp. 14-40, doi:10.21585/ijcses.v2i1.23.