V. Devedzic, J. Good, A. Harrer, R. Luckin, D. Pearce, S. Retalis, и J. Robertson. Artificial Intelligence in Education - Building Technology Rich Learning Contexts that Work, том 158 из Frontiers in Artificial Intelligence and Applications, стр. 715. Amsterdam, IOS Press, (2007)
J. Coplien. Proceedings of the 2nd European Conference on Pattern Languages of Programming (EuroPLoP '97). Siemens Technical Report 120/SW1/FB, стр. 51-60. Munich, Germany, Siemens, (1997)