1. COGGINS, J. C. W. and HIELD, H. Z. (1968). Plant growth regulators. In:Citrus industry,III, 371–89. University of California Press, Berkeley.
2. COHEN, A. (1972b). Factors affecting fruitlet drop and yield of citrus trees.Hassadeh,52, 747–850 [Hebrew]
3. COHEN, A. (1982). Recent developments in girdling of citrus trees.Proceedings of the International Society of Citriculture(in press).
4. DAMIGELLA, P., TRIBULATO, E. and CONTINELLA, G. (1970). Comparative trials with gibberellic acid, girdling and foliar fertilizing on clementines.Technica Agricola,22, 508–25 [Italian].
5. FISCHLER, M. and SZIVOS, Y. (1978), Summer girdling of grapefruit trees in the inland valleys.Hassadeh,58, 2266–71 [Hebrew].