Yari, M. and Khadwmol Hosseini, N. (2010). Effect of Operator’s Age, Formal Education and Technical Level on Variable Costs of Convertional Tractors at Arak Town Countries. Agricultural Engineering, 1.32(Published articles (periods 1 to 32) in the field of agricultural engineering before the separation of the scientific journal of agriculture in the years 1975-2009), 49-57. doi: 10.22055/agen.2010.15460

Yari, M. , and Khadwmol Hosseini, N. . "Effect of Operator’s Age, Formal Education and Technical Level on Variable Costs of Convertional Tractors at Arak Town Countries", Agricultural Engineering, 1.32, Published articles (periods 1 to 32) in the field of agricultural engineering before the separation of the scientific journal of agriculture in the years 1975-2009, 2010, 49-57. doi: 10.22055/agen.2010.15460

Yari, M., Khadwmol Hosseini, N. (2010). 'Effect of Operator’s Age, Formal Education and Technical Level on Variable Costs of Convertional Tractors at Arak Town Countries', Agricultural Engineering, 1.32(Published articles (periods 1 to 32) in the field of agricultural engineering before the separation of the scientific journal of agriculture in the years 1975-2009), pp. 49-57. doi: 10.22055/agen.2010.15460

M. Yari and N. Khadwmol Hosseini, "Effect of Operator’s Age, Formal Education and Technical Level on Variable Costs of Convertional Tractors at Arak Town Countries," Agricultural Engineering, 1.32 Published articles (periods 1 to 32) in the field of agricultural engineering before the separation of the scientific journal of agriculture in the years 1975-2009 (2010): 49-57, doi: 10.22055/agen.2010.15460

Yari, M., Khadwmol Hosseini, N. Effect of Operator’s Age, Formal Education and Technical Level on Variable Costs of Convertional Tractors at Arak Town Countries. Agricultural Engineering, 2010; 1.32(Published articles (periods 1 to 32) in the field of agricultural engineering before the separation of the scientific journal of agriculture in the years 1975-2009): 49-57. doi: 10.22055/agen.2010.15460