Mackay, A., A. Gillingham, C. Smith, P. Budding, P. Phillips, W. Clarke-Hill, and P. Johnstone. “Effect of Soil Physical Condition, and Phosphorus and Nitrogen Availability on Pasture Persistence”. NZGA: Research and Practice Series, vol. 15, Jan. 2011, pp. 85-91, doi:10.33584/rps.15.2011.3209.