1. Badr, M. & W. Horn, 1971. Genetische Untersuchungen an Diploiden und Tetraploiden Pelargonium zonale-Hybriden. Z. Pflanzenzüchtg. 66: 203–220.
2. Ballard, W.R., 1918. Notes on geranium breeding. Proc. Amer. Soc. Hort. Sci. 15: 62–5.
3. Barnhart, D, 1957. Preliminary observations on a geranium breeding project. Geraniums Around the World 5: 15–6.
4. Chittenden, F.J., 1951. (Ed.). The Royal Horticultural Society Dictionary of Gardening: A Practical and Scientific Encyclopaedia of Horticulture. Vol. III: JE-PT. Clarendon Press, Oxford.
5. Chow, T.W. & P.M. Harney, 1970. Crossability between a diploid Pelargonium x hortorum Bailey cultivar and some of its putative ancestral species. Euphytica 19: 338–48.