Keywords: Postzegel 1923 jubileum.jpg Willem van Konijnenburg en Jan van Krimpen letters en cijfers scanned from own collection 2007-10-01 Wouter Hagens PD-old Stamps of the Netherlands 1923-1926 Wilhelmina of the Netherlands on stamps 1923 stamps People of the Netherlands on stamps Jan van Krimpen Willem van Konijnenburg |