[1]
A. Pekkarinen and L. Huldén, “Distribution and phenology of the <i>Ancistrocerus</i> and <i>Symmorphus</i> species in eastern Fennoscandia (Hymenoptera, Eumenidae)¹”, Entomol. Fennica, vol. 2, no. 3, pp. 179–189, Sep. 1991.