1. Plamenac N.(1962):Laboratory apparatus and method for the serial determination of the filtration properties of soils. Review “Tehnika” Belgrade.
2. Stewart T. H.(1960):Land and water Resources of Tripolitania – Libya; Tripoly.
3. Die Bestimmung des Kalibedarfs im Boden
4. USDA(1954): Handbook No 60 — Diagnosis and Improvement of Saline and Alkali Soils. Gov't Printing Office Washington D.C.