1st Internship of Benjamin Jacob Heertje1st Internship of Gerardus Hendrikus Hazelaar1st Internship of Evert Karel Hofstede4th Internship of Johannes Frederik Kok1st Internship of Jacobus Kroese2nd Internship of Jan Hendrik Moorman1st Internship of Pieter Marinus ter Veen1st Internship of Albertus Hendrik ter Veen1st Internship of Daniël Bakels