TY - JOUR T1 - Effect of Hours of Use and Age in Years in Estimating Repair and Maintenance Costs for Two Sizes of Agricultural Tractors in Northern Sudan JO - Journal of Agronomy Research VL - 4 IS - 2 SP - 1 EP - 11 PY - 2021/2// T2 - AU - Mohamed, Hassan Dahab AU - Abdalla, N. O. Kheiry AU - Montasir, Ahmed Gafar Elfaki SN - 2639-3166 DO - https://doi.org/10.14302/issn.2639-3166.jar-21-3875 UR - https://openaccesspub.orgjar/article/1710 KW - Repair and Maintenance KW - purchase price KW - Hours of Use KW - Age KW - Tractor KW - New Halfa. ER -