Van Basis Tot Limiet 5/6, Leerwerkboek Statistiek, Leerplan C, Uitgeverij die Keure (ISBN 978 90 8661 878 1). This edition is meant for 3rd grade pupils/students TSO/KSO (VVKSO) (Technisch Secundair Onderwijs) subject Maths/Statistics. On page 112 of this workbook or exercise book Statistics, one of my military photos was printed because it's related to a Belgian researcher, Adolphe Quetelet, who investigated around 1817 data of Scottish soldiers regarding weight, height etc. to find the 'average' person. Quetelet is renown for finding the now popular Body Mass Index (BMI).