1. Estimation of genie similarity within and between Arion hortensis s.l. and A. intermedius by means of isoelectric focused esterase patterns in hepato-pancreas homogenates (Mollusca, Pulmonata: Arion-idae;Backeljau;Z. Zool. Syst. Evolut.-forsch.,1985
2. Electrophoretic distinction between Arion hortensis, A. distinctus and A. owenii (Mollusca: Pulmonata;Backeljau;Zool. Anz.,1987
3. On the infrageneric systematics of the genus Arion Férussac, 1819 (Mollusca, Pulmonata;Backeljau;Bull. Inst. R. Sci. Nat. Belg., Biol.,1990
4. Preliminary report on the genetic variability of Arion intermedius in Europe (Pulmonata;Backeljau;J. Med. Appl. Malacol.,1991
5. Colour polymorphism and genetic strains in Arion intermedius from Flores, Azores (Mollusca: Pulmonata;Backeljau;Biol. J. Linn. Soc.,1992