J. G. Baker: Refugium Botanicum; or, Figures and Descriptions from Living Specimens of Little Known of New Plants of Botanical Interest. Band 1, London 1869, Tafel 59 (online).
biodiversitylibrary.org
Eduard Otto: Hamburger Garten- und Blumenzeitung. 29. Jahrgang, Hamburg 1873, Seite 8 (online).
