BRIEF OHNE UMSCHLAG Haeckel, Ernst Author: Haeckel, Ernst Recipient: Linck, Gottlob Dating: 05.10.1912
BRIEF [O.A.] Recipient: Haeckel, Ernst Corporation: Apollowerk G.m.b.H., Kunstanstalt und Verlag Dating: 27.08.1912
BRIEF [O.A.] Belford, Robert J... Author: Belford, Robert J... Recipient: Haeckel, Ernst Corporation: Typewriter Silencer Mfrs. Dating: 25.03.1912
BRIEF [O.A.] Belford, Robert J. Author: Belford, Robert J. Recipient: Haeckel, Ernst Corporation: Typewriter Silencer Mfrs. Dating: 14.06.1912
BRIEF OHNE UMSCHLAG Belford, Robert J. Author: Belford, Robert J. Recipient: Haeckel, Ernst Corporation: Belford & Company Publishers Dating: 16.12.1912