Hoffmann, Hermann. 1881. Rückblick auf meine Variations-Versuche von 1855–1880. Botanische Zeitung, 3 June 1881, pp. 345–51; 10 June 1881, pp. 361–8; 17 June 1881, pp. 377–83; 24 June 1881, pp. 393–9; 1 July 1881, pp. 409–15; 8 July 1881, pp. 425–32.
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