2. Ritson, C. Gofton L, Me Kenzie J. The food consumer . John Willey & sons New york 1986.
3. Hayes G.D. Food engineering data hand book. Longman Scientific and technical New York 1987
4. Bemder , FE. , Kramer, A. , Kahan , G. System analysis for the food industries AVI Publication .Co. Connecticut. 1976