BRIEF OHNE UMSCHLAG Mulder, Lodewijk Author: Mulder, Lodewijk Recipient: Haeckel, Ernst Dating: 15.02.1894
BRIEF OHNE UMSCHLAG Mulder, J. A., de Villeneuve Author: Mulder, J. A., de Villeneuve Recipient: Haeckel, Ernst Dating: 14.05.1907
BRIEF OHNE UMSCHLAG Mulder, Lodewijk Author: Mulder, Lodewijk Recipient: Haeckel, Ernst Dating: 12.09.1890
BRIEF OHNE UMSCHLAG Mulder, Aldegonde Author: Mulder, Aldegonde Recipient: Haeckel, Ernst Dating: 10.10.1907
BRIEF OHNE UMSCHLAG Mulder, Aldegonde Author: Mulder, Aldegonde Recipient: Haeckel, Ernst Dating: 31.07.1907