Popp, M., B. Badarch, A. Poncet, S. Rider, and N. Slaton. “Economically Optimal Soil Sampling Density and Application Technology for Potassium Fertilizer for Soybean in the Mid-Southern US”. Research on World Agricultural Economy, vol. 6, no. 4, Aug. 2025, pp. 766-83, doi:10.36956/rwae.v6i4.1789.