Blumenbach, J.F. 1784. Letter to Johann Heinrich Merck in Darmstadt, dated Göttingen, 2 January 1784. In: Dougherty, F.W.P.; Klatt, N. 2007. The Correspondence of Johann Friedrich Blumenbach, Volume II: 1783-1785 Letters 231 – 391. Revised, Augmented and Edited by Norbert Klatt. Göttingen, Klatt. pp. 125-127 (printed and annotated).