Details
RUDOLF PRESSLER Illustrierter katalog Nr.L.1 Werksttten fr elektrische Vakuumrhren, physikalische und chemische Lehrmittel Cursdorf 1927;
and RUDOLF PRESSLER Electric Vacuum-Tubes for Educational purposes and Induction Coils, Edition V2 (page 46 cut), original catalogues, colour covers, line drawings with text (2)
and RUDOLF PRESSLER Electric Vacuum-Tubes for Educational purposes and Induction Coils, Edition V2 (page 46 cut), original catalogues, colour covers, line drawings with text (2)