1. USDA National Agriculture Statistics Service (NASS), National Hop Report (2013). Available at: http://www.nass.usda.gov/Statistics_by_State/Washington/Publications/Hops/index.asp (Accessed: 12th Oct 2015).
2. Barth-Haas Group, The Bath Report-Hops 2013/2014. (2014) Available at: http://www.barthhaasgroup.com/en/news-and-reports/the-barth-report-hops . (Accessed: 12th Oct 2015).
3. Neve, R. A. In Hops. (ed. Neve, R. A. ) 1–272 (Chapman and Hall, London, 1991).
4. Clarke, B. J. Hop products. J. Inst. Brew. 92, 123–130 (1986).
5. USAHOPS.ORG, Hop growing in Washington. (2008) Available at: http://www.usahops.org/ (Accessed: 12th Oct 2015).