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Drester                                 founded in 1978

    

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IRT                                         founded in 1967

    

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Hedson Technologies       founded in 1999  as a result of a merge between Drester and IRT

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Formo Services                   acquired Hedson 2004

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Herkules                               founded in 1974 was acquired by Hedson in 2005      

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Trisk                                       founded in 1988 was acquired by Hedson in 2006