Troels-Smith, J. “Ivy, Mistletoe and Elm Climate Indicators - Fodder Plants. A Contribution to The Interpretation of the Pollen Zone Border VII-VIII”. Danmarks Geologiske Undersøgelse IV. Række, vol. 4, no. 4, Dec. 1960, pp. 1-32, doi:10.34194/raekke4.v4.7000.