Abo-Elnor, M., Hamilton, R. and Boyle, J. T. 2004. Simulation of soil-blade interaction for sandy soil using advanced 3D finite element analysis. Soil & Till. Res. 75(1): 61-73.

Abu-Hamdeh, N. H. and Reeder, R. C. 2003. A nonlinear 3D finite element analysis of the soil forces acting on a disk plow. Soil & Till. Res. 74(2): 115-124.

Anon. 1983. RNAM Test Codes & Procedures for Farm Machinery. Technical Series No. 12.

Anon. 2003. Agricultural Statistic. Ministry of Jihad-e- Agriculture. Center of Development of Mechanization. Tehran. Iran. (in Farsi)

Barrett, F. M. 1967. A helical design for plough mouldboard. J. Agric. Eng. Res. 12(3): 178-183.

Bernacki, H., Haman, J. and Kanufoiski, C. Z. 1972. Agricultural Machines: Theory and Construction. Springfield VA. 22161. Technical Information Service. U.S. Department of Commerce.

Bukhari, S., Bhutto, M. A., Baloch, J. M., Bhutto, A. B. and Mirani, A. N. 1988. Performance of selected tillage implements. AMA. 19(4): 9-14.

Bukhari, S., Bhutto, M. A., Baloch, J. M., Bhutto, A. B., Mari, G. R. and Mirani, A. N. 1990. Effect of different speeds on the performance of moldboard plow. AMA. 21(1): 27-31.

Fielke, J. M. 1999. Finite element modelling of the interaction of the cutting edge of tillage implements with soil. J. Agric. Eng. Res. 74(1): 91-101.

Formato, A., Faugno, S. and Paolillo, G. 2005. Numerical simulation of soil-plough mouldboard interaction. Biosys. Eng. 92 (3): 309-316.

Goryachkin, V. P. 1968. Collocted Works in Three Volumes. 2^nd Ed. TT71-50087. Sprinfield VA: Nat. Technical Information Service. U.S. Department of Commerce.

Gyachev, L. V. 1961. Teoria lemshnovo-ofval' noi poverkhnosti (Theory of share-moldboard surface). Reports of Azov-Black Sea Inst. Mech. Agric. Zernograd. (in Russian)

Kafashan, J. 1997. Design of moldboard using computerized graphic. M. Sc. Thesis. Department of Mechanics of Agricultural Machinery. Tarbiat Modarres University. Tehran. Iran. (in Farsi)

Kianmehr, M. H., Khazaei, J. and Hassan-Beygi, S. R. 2005. Design, development and evaluation a three bottom two-way square plow. Proceedings of International Congress of Information Technology in Agriculture, Food and Environment (ITAFE'05). Oct. 10-12. Adana. Turkey. 

Loghavi, M. and Behnam, S. 1998. Effect of soil moisture and tillage depth on disk plow performance at a loam clay soil. J.. Agric. Sci. Natur. Resour. 1(2): 85- 96. (in Farsi)

Mouazen, A. M. and Nemenyi, M. 1998. A review of the finite element modelling techniques of soil tillage. Mathematics and Computers in Simulation. 48, 23-32.

Mouazen, A. M. and Nemenyi, M. 1999a. Finite element analysis of subsoiler cutting in non-homogeneous sandy loam soil. Soil & Till. Res. 51(1-2): 1-15.

Mouazen, A. M. and Nemenyi, M. 1999b. Tillage tool design by the finite element method: Part 1. Finite element modelling of soil plastic behaviour. J. Agric. Eng. Res. 72(1): 37–51.

Mouazen, A. M., Nemenyi, M., Schwanghart, H. and Rempfer, M. 1999. Tillage tool design by the finite element method: Part 2. Experimental validation of the finite element results with soil bin test. J. Agric. Eng. Res. 72(1): 53-58.

Planeta, A. and Peri, G. 1988. A computerized mathematical model of a mouldboard plough surface. Revista di Ingineria Agraia Guaderno. No. 10, 823-829.

Plouffe, C., Richard, M. J., Tessier, S. and Lague, C. 1999. Validations of moldboard plow simulations with FEM on a clay soil. Trans. ASAE, 42(6): 1523-1529.

Raper, R. L. and Erbach, D. C. 1990. Prediction of soil stresses using finite element method. Trans. ASAE. 33(3): 725-730.

Richey, S. B., Srivastava, A. K. and Segerlind, L. J. 1989. The use of three dimensional computer graphics to design mouldboard plough surfaces. J. Agric. Eng. Res. 43, 245-258.

Ros, V., Marley, S. J., Smith, R. J. and Erbach, D. C. 1993. Analysis of tillage tool geometry. Paper No. 93-1091. ASAE. St. Joseph. MI. 49085-9659. USA.

Ros, V., Smith, R. J., Marley, S. J. and Erbach, D. C. 1995. Mathematical modeling and computer-aided design of passive tillage. Trans. ASAE. 38(3): 675-683.

Shrestha1, D. S., Singh, G. and Gebresenbet, G. 2001. Optimizing design parameters of a mouldboard plough. J. Agric. Eng. Res. 78 (4): 377-389.

Smith, D. W., Sims, B. G. and Oneill, D. H. 1994. Testing and Evaluation of Agricultural Machinery and Equipment. Principles and Practices. Bulletin No. 110. FAO. Rome. Italy

Sochne, W. 1959. Investigation on the shape of plough bodies. Grundlangen der Landteknic. 11(16-17): 223-23.

Solhjoo, A., Loghavi, M., Ahmadi, H. and Roozbeh, M. 2001. Effect of soil moisture percent and tillage depth on soil breaking rate and reduction of secondary tillage operation. J. Agric. Eng. Res. 6(2): 1-11. (in Farsi)

Tabatabaeefar, A. 1999. Comparison of tractor drawbar power at different direction of tillage on slope. J. Agric. Sci. 19(5): 49-58. (in Farsi)

Tabatabeefar, A. and Safari, M. 2001. Determination of field efficiency and cost of moldboard plow and disk harrow operations in Kermanshah city. J. Agric. Eng. Res. 6(2): 33-43. (in Farsi)

Tabatabaeefar, A. and Omid, M. 2005. Current status of Iranian agricultural mechanization. J. Agric. Soc. Sci. 1(2): 196-201.

Wainwright, R. P., Buchele, W. F., Marley, S. J. and Boldwin, W. L. 1983. A variable approach angle mouldboard plow. Trans. ASAE. 26(2): 396-400.