P. C. de Jong: Flowering and sex expression in Acer L.: a biosystematic study. Dissertation, Wageningen 1976, S. 78, Fig. 26, PDF.
P. C. de Jong: Flowering and sex expression in Acer L.: a biosystematic study. Dissertation, Wageningen 1976, S. 78, 103, 127, 131, 147 f, Fig. 3, 25, PDF.