TELEGRAMM Thoden van Velzen, S... K... Author: Thoden van Velzen, S... K... Recipient: Haeckel, Ernst Dating: 16.02.1913
BRIEF [O.A.] Thoden van Velzen, S... K... Author: Thoden van Velzen, S... K... Recipient: Haeckel, Ernst Dating: 02.01.1913
BRIEF [O.A.] Thoden van Velzen, S... K... Author: Thoden van Velzen, S... K... Recipient: Haeckel, Ernst Dating: 31.03.1913
BRIEF [O.A.] Thoden van Velzen, S... K... Author: Thoden van Velzen, S... K... Recipient: Haeckel, Ernst Dating: 30.06.1913
BRIEF [O.A.] Thoden van Velzen, S... K... Author: Thoden van Velzen, S... K... Recipient: Haeckel, Ernst Dating: 04.09.1913
BRIEF OHNE UMSCHLAG Thoden van Velzen, Elfriede Author: Thoden van Velzen, Elfriede Recipient: Haeckel, Agnes Dating: 04.12.1913