P. J. Felder

• Excavations of prehistoric flint mines at Rijckholt-St. Geertruid (Limburg, The Netherlands)
• Excavations of prehistoric flint mines at Rijckholt-St. Geertruid (Limburg, The Netherlands) by the 'Prehistoric Flint Mines Working Group' of the Dutch Geological Society, Limburg Section
• Geologische bezienswaardigheden in het Mergelland