B. Brehmer, and D. Doerner. Computers in Human Behavior Special Issue: Swedish research on learning and instruction with computers, 9 (2-3):
171--184(1993)
J. Strodl, K. Doerner, F. Tricoire, and R. Hartl. Hybrid Metaheuristics, volume 6373 of Lecture Notes in Computer Science, page 160-173. Springer, (2010)