1st Internship of Antonius Bos2nd Internship of Jacoba H. Hessels1st Internship of Albertus Johannes Franciscus Hooning2nd Internship of Juste Christiaan Lang3th Internship of Jan Adrianus Cornelis Kok1st Internship of Jan Mulder2nd Internship of Jacobus Johannes Reddering1st Internship of Willem Johannes Petrus Spronk2nd Internship of Johannes P. Webbers1st Internship of Dirk Beek