Brown, K., Lill, G., Mccartin, J., Jarman, D., Mccloy, B., Hampton, J., Rolston, M., Stewart, A. and White, J. 1990. RYEGRASS SEED CROPS. NZGA: Research and Practice Series. 5, (Jan. 1990), 40–46. DOI:https://doi.org/10.33584/rps.5.1998.3339.