R. Saikkonen, L. Malmi, and A. Korhonen. Proceedings of the 6th annual conference on Innovation and technology in computer science education, page 133--136. New York, NY, USA, ACM, (2001)
L. Malmi, A. Korhonen, and R. Saikkonen. Proceedings of the 7th annual conference on Innovation and technology in computer science education, page 55--59. New York, NY, USA, ACM, (2002)