ČEH, Barbara, ČERENAK, Andreja in MAJER, Dušica, 2009, Potassium and proline content in hop leaves as biochemical marker for drought stress tolerance. Hmeljarski bilten [na spletu]. 2009. Vol. 16, p. 43–52. [Dostopano 15 marec 2025]. Pridobljeno s: http://www.dlib.si/details/URN:NBN:SI:DOC-1SRDDJYS