IQ and Psychometric Test Workbook IQ and Psychometric Test Workbook
2011
Altar of Bones Altar of Bones
2011
The Complete Book of Fun Maths The Complete Book of Fun Maths
2009
Logikrätsel für Schlaumeier Logikrätsel für Schlaumeier
2007
Der IQ-Test Der IQ-Test
2005
Ultimate IQ Tests Ultimate IQ Tests
2015