1. Joachim Wolschke-Bulmahn, “The Search for ‘Ecological Goodness’ among Garden Historians,” in Perspectives on Garden Histories, ed. by Michel Conan (Washington D.C.: Dumbarton Oaks Research Library and Collection, 1999), 161-180
2. Joachim Wolschke-Bulmahn, “The ‘Wild Garden’ and the ‘Nature Garden’ — Aspects of the Garden Ideology of William Robinson and Willy Lange,” The Journal of Garden History 12, no. 3 (1992): 183-206
3. Willy Lange, Gartengestaltung der Neuzeit (Leipzig: J.J. Weber, 1907)
4. Leo Kloss, “Blühende Wiesen statt Teppichrasen,” Die Gartenkunst 50, no. 5 (1937): 119-121
5. Sonja Dümpelmann, Seeing Trees: A History of Street Trees in New York City and Berlin (New Haven and London: Yale University Press, 2019)