Inventor: Scheffers, Robertus
Inventor: Scheffers, Robertus
Inventor: Bak, Elly, Steur, Nicolaas D. M.
Inventor: Bak, Elly, Steur, Nicolaas D. M.
Inventor: Koning, Lammert
Inventor: Koning, Lammert
Inventor: Koning, Lammert
Inventor: Koning, Lammert
Inventor: Koning, Lammert
Inventor: Koning, Lammert
Inventor: van den Burg, Gerardus Pieter