1. SWARBRICK, F. (1945). Use of growth promoting substances in the prevention of apple
2. WRIGHT, S. T. C. (1968). Multiple and sequential roles of plant growth regulators. In “Biochemistry and physiology of plant growth substances”, 521–42. Ed. Wightman, F., and Setterfield, G.Proc. 6th int. Conf. on Pl. Growth Subst., Ottawa. Runge Press, Ottawa.