Laasonen, E. and Laasonen, L. 2000. Habitual differences of Phyllonorycter salictella (Zeller, 1846 ) and P. heringiella ( Grönlien, 1932) (Lepidoptera: Gracillariidae) in two Finnish materials; a problem pair. Entomologica Fennica. 11, 3 (Sep. 2000), 175–181. DOI:https://doi.org/10.33338/ef.84063.