POSTKARTE Thoden van Velzen, Hendrik Author: Thoden van Velzen, Hendrik Recipient: Haeckel, Ernst Dating: 03.06.1912
POSTKARTE Thoden van Velzen, Hendrik Author: Thoden van Velzen, Hendrik Recipient: Haeckel, Ernst Dating: 03.02.1912
BRIEF OHNE UMSCHLAG Thoden van Velzen, Hendrik Author: Thoden van Velzen, Hendrik Recipient: Haeckel, Ernst Dating: 20.09.1912
POSTKARTE Thoden van Velzen, S... K... Author: Thoden van Velzen, S... K... Recipient: Haeckel, Ernst Dating: 27.12.1916
POSTKARTE Thoden van Velzen, Syo Kornelius Author: Thoden van Velzen, Syo Kornelius Recipient: Haeckel, Ernst Dating: 14.11.1916
POSTKARTE Thoden van Velzen, Hendrik Author: Thoden van Velzen, Hendrik Recipient: Haeckel, Ernst Dating: 27.12.1918
POSTKARTE Thoden van Velzen, S... K... Author: Thoden van Velzen, S... K... Recipient: Haeckel, Ernst Dating: 09.07.1913
POSTKARTE Thoden van Velzen, Hendrik Author: Thoden van Velzen, Hendrik Recipient: Haeckel, Ernst Dating: 24.11.1913
POSTKARTE Thoden van Velzen, Hendrik Author: Thoden van Velzen, Hendrik Recipient: Haeckel, Ernst Dating: 29.12.1915
BRIEF [O.A.] Thoden van Velzen, Hendrik Author: Thoden van Velzen, Hendrik Recipient: Haeckel, Ernst Dating: 14.02.1914