Scheer , W. “Vegetable Oils As Substitution for Diesel Oil: Test Results Obtained on a Diesel Engine With Direct Injection”. Zede Journal of Ethiopian Engineers and Architects 7 (January 31, 2023): 35–40. Accessed June 7, 2025. https://ejol.aau.edu.et/index.php/ZEDE/article/view/6194.