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2. Manfred Hesse, Alkaloids: Nature’s Curse or Blessings, Wiley-VCH, 2002 (see Index).
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4. P. Karrer and Rose Widmer, Die Konfiguration des Nicotins. Optisch active Hygrinsäure, Helv. Chim. Acta, 1925, 8, 364-368
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