Cogo, C. M., Andriolo, J. L., Bisognin, D. A., Godoi, R. dos S., Bortolotto, O. C., & da Luz, G. L. (2006). Nitrogen-potassium relationship for diagnosis of plant nutritional status and fertilization of the potato crop. Pesquisa Agropecuaria Brasileira, 41(12), 1781–1786. https://doi.org/10.1590/S1678-3921.pab2006.v41.7345