Yablokov, A. V., Eatin, V. J., & Pritikina, L. N. (1970). Variability of wing venation of the dragonfly. Beiträge Zur Entomologie = Contributions to Entomology, 20(5-6), 503–526. https://doi.org/10.21248/contrib.entomol.20.5-6.503-526