BRIEF [O.A.] Beck, Alberto Author: Beck, Alberto Recipient: Haeckel, Ernst Corporation: Mineral de San Sebastian Dating: 18.01.1902
BRIEF OHNE UMSCHLAG Beck, Alberto Author: Beck, Alberto Recipient: Haeckel, Ernst Corporation: Mineral de San Sebastian Dating: 05.12.1902
BRIEF [O.A.] Beck, Alberto Author: Beck, Alberto Recipient: Haeckel, Ernst Corporation: Mineral de San Sebastian Dating: 11.05.1903
BRIEF [O.A.] Beck, Alberto Author: Beck, Alberto Recipient: Haeckel, Ernst Corporation: Mineral de San Sebastian Dating: 18.03.1903
BRIEF [O.A.] Zentella, Arcadio Author: Zentella, Arcadio Recipient: Haeckel, Ernst Corporation: Instrucción Pública Dating: 08.02.1910
BRIEF [O.A.] Zentella, Arcadio Author: Zentella, Arcadio Recipient: Haeckel, Ernst Corporation: Instrucción Pública Dating: 26.08.1908
ANSICHTSKARTE Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 03.03.1910
TELEGRAMM Rottenburg, Paul von Author: Rottenburg, Paul von Recipient: Haeckel, Ernst Dating: 16.02.1910
BRIEF [O.A.] Rovirosa, F... Lacroix Author: Rovirosa, F... Lacroix Recipient: Haeckel, Ernst Dating: 02.03.1909