VARSHNEY, A. C., NAIK, R. K., NANDY, S. M., PRAJAPATI, G. S., & NARANG, S. (2011). Determination of angle of penetration of soil working tools in clay soil. The Indian Journal of Agricultural Sciences, 76(1). https://epubs.icar.org.in/index.php/IJAgS/article/view/2597