Burt, Charles M.; Styles, Stuart W. (1999). Drip and Micro Irrigation for Trees, Vines, and Row Crops (2nd ed.). San Luis Obispo, CA: Irrigation Training and Research Center (ITRC) - Cal Poly. pp. 13–26. ISBN 0-9643634-2-9. 0-9643634-2-9 ↩
http://ufdcimages.uflib.ufl.edu/UF/00/00/85/33/00001/00010.pdf [bare URL PDF] http://ufdcimages.uflib.ufl.edu/UF/00/00/85/33/00001/00010.pdf ↩