1. Alston, F.H., 1969. Response of apple cultivars to mildew, Podosphaera leucotricha. Rep E Malling Res Stn 1968: 133–135.
2. Alston, F.H., 1983. Progress in transferring mildew (Podosphaera leucotricha) resistance from Malus species to cultivated apple. Bulletin IOBC wprs 6(4): 87–95.
3. Brown, A.G., 1959. The inheritance of mildew resistance in progenies of the cultivated apple. Euphytica 8: 81–88.
4. Butt, D.J., 1978. Epidemiology of powdery mildews. In: D.M. Spencer (Ed.), The powdery mildew, pp. 51–81. Academic press, London, UK.
5. Caffier, V. & F. Laurens, 2005. Breakdown of Pl2, a major gene of resistance to apple powdery mildew, in a French experimental orchard. Plant Pathology 54: 116–124.