Holb, I. J. “Apple Powdery Mildew Caused by Podosphaera Leucotricha: Some Important Features of Biology and Epidemiology”. International Journal of Horticultural Science, vol. 15, no. 1-2, Mar. 2009, pp. 45-51., https://doi.org/10.31421/IJHS/15/1-2/811.