Chapman, D., Ludemann, C., Griffiths, W., Rossi, L., Waugh, D. and Kuhn-Sherlock, B. 2021. Persistence of the yield advantage of perennial ryegrass cultivars: concept, evidence and implications . NZGA: Research and Practice Series. 17, (Jun. 2021), 411–420. DOI:https://doi.org/10.33584/rps.17.2021.3452.