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   Hans M. Heybroek
   Hans M. Heybroek (1927- ) is a Dutch botanist best known for his researches into the genus Ulmus at the Dorschkamp Research Institute for Forestry & Landscape Planning. Until his retirement in 1992, he was responsible for the raising and release of numerous elm hybrid cultivars, notably `Columella`...
   Found op http://en.wikipedia.org/wiki/Hans_M._Heybroek
   
   

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