1st Internship of Franciscus Keune3th Internship of Johan Pieter de Leth1st Internship of Nicolaas Ger. Kuulkers1st Internship of Petrus Cornelis van Leeuwen1st Internship of Gerrit Panhuise3th Internship of Carl Ferdinand Rooke2nd Internship of Cornelis Christiaan Slop1st Internship of Cornelis Johannes de Vries1st Internship of Gerardus Petrus Leonardus de Vries