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  1. The affinities of the North American species of Gomphus as revealed by the genitalia (Odonata, Gomphidae) /
    By: Walker, E. M. - Royal Ontario Museum.
    Publication info: Toronto :Royal Ontario Museum,1957.
    Contributed by: ROM - University of Toronto (archive.org)
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  2. Insects. Part J Orthoptera /
    By: Walker, E. M. - Canadian Arctic Expedition
    Publication info: Ottawa :T. Mulvey,1920.
    Contributed by: Canadiana.org (archive.org)
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