Gobran, GR., Dufey, J., & Laudelout, H. (1982). The Use of Gypsum for Preventing Soil Sodification - Effect of Gypsum Particle-size and Location in the Profile. Journal of Soil Science, 33(2), 309-316. https://doi.org/10.1111/j.1365-2389.1982.tb01768.x (Original work published 1982)