Fraser, T., S. Dennis, R. Moss, K. Tozer, N. Stocker, A. Taylor, M. Faville, and C. Smith. “Long Term Effect of Superphosphate Fertilisers on Pasture Persistence”. NZGA: Research and Practice Series, vol. 15, Jan. 2011, pp. 93-97, doi:10.33584/rps.15.2011.3210.