Ussher, G.R., and D.E. Hume. “Sustainable Perennial Pastures in Northland”. Journal of New Zealand Grasslands 77 (January 1, 2015): 141–146. Accessed November 6, 2026. https://www.nzgajournal.org.nz.myth.agency/index.php/JoNZG/article/view/489.