Geometrie im Alltag
In: Mathematik lehren, Jg. 29, S. 8-14Geometry in everyday life
In: Articles on mathematics education: Erkki Pehkonen, Jg. 55, S. 11-23Problem-orientated geometry teaching : with consideration of computers
In: Geometry teaching: Geometrieunterricht ; Conference on the Teaching of Geometry in Helsinki, 1. - 4.8.1989, Jg. 74, S. 141-1501989