Y. A. Pesenko, Banaszak, J., Radchenko, V. G., and Cierzniak, T., Bees of the family Halictidae (excluding Sphecodes) of Poland: taxonomy, ecology, bionomics. Bydgoszczy: Wydawnictwo Uczelniane Wyższej Szkoły Pedagogicznej w Bydgoszczy, 2000.

C. D. Michener, The bees of the world. Baltimore: Johns Hopkins University Press, 2000.

M. E. Archer, The British potter and mason wasps: a handbook. York:  Vespid Studies, 2000.

T. Benton, The Bumblebees of Essex. Lopinga Books, 2000.

M. Blösch, Die Grabwespen Deutschlands: Lebensweise, Verhalten, Verbreitung, vol.  71. 2000.

O. Niehuis, “The European species of the Chrysis ignita group: revision of the Chrysis angustula aggregate (Hymenoptera, Chrysididae)”, Mitteilungen aus dem Museum für Naturkunde in Berlin, Deutsche Entomologische Zeitschrift, vol. 47, pp. 181-201, 2000.

S. F. Gayubo and Felton, J. C., “The European species of the genus Nitela Latreille, 1809 (Hymenoptera: Sphecidae)”, Annales de la Société entomologique de France (N.S.),, vol. 36, pp. 291-313, 2000.

J. Straka, “Faunistic records from the Czech Republic – 109. Hymenoptera:Aculeata”, Klapalekiana, vol. 36, pp. 181-183, 2000.

Y. R. Wu, Hymenoptera. Melittidae, Apidae. 2000.

G. M. Orledge, Smith, P. A., and David, C., “Leptothorax albipennis (Curt is) and other Leptothorax ants in the Channel Islands”, Report and Transactions of La Société Guernesiaise, vol. 24, pp. 862-866, 2000.

V. V. Vikberg, “A re-evaluation of five European species of Spilomena with a key to European species and relevance to the fauna of North Europe, especially Finland (Hymenoptera: Pemphredonidae)”, Entomologica Fennica, vol. 11, pp. 35-55, 2000.

D. A. Bond and Kirby, E. J. M., “Anthophora plumipes (Hymenoptera: Anthophoridae) as a pollinator of broad bean (Vicia faba major)”, Journal of Apicultural Research, vol.  38, pp.  199-203, 1999.

D. Mader, Geologische und biologische Entomoökologie der rezenten Seidenbiene Colletes. Köln: Logabook, 1999.

M. Olmi, Hymenoptera Dryinidae-Embolemidae. 1999, pp. 1-425.

G. R. Else, “Identification. Leaf-cutter bees”, British Wildlife, vol. 10, pp. 388-392, 1999.

S. P. M. Roberts, “Purbeck Mason-wasp, Pseudepipona herrichii (Saussure) (Hymenoptera Aculeata: Eumenidae)”, 1999.

R. J. Paxton and Pohl, H., “The tawny mining bee, Andrena fulva (Müller) Hymenoptera, Andreninae), at a south Wales field site and its associated organisms: Hymenoptera, Diptera, Nematoda and Strepsiptera”, British Journal of Entomology and Natural History, vol. 12, pp. 57-67, 1999.

M. E. Archer, “Taxonomy and world distribution of the Euro-Asian species of Dolichovespula (Hym., Vespinae)”, Entomologist’s Monthly Magazine, vol.  135, pp.  153-160, 1999.

T. M. J. Peeters, Raemakers, I. P., and Smit, J., Voorlopige atlas van de Nederlandse bijen (Apidae). Leiden: EIS-Nederland, 1999.

T. M. J. Peeters, Raemakers, I. P., and Smit, J., Voorlopige atlas van de Nederlandse bijen (Apidae). Leiden: EIS-Nederland , 1999.

S. G. Potts and Wilmer, P., “Compact housing in built-up areas: spatial patterning of nests in aggregations of a ground-nesting bee”, Ecological Entomology, vol. 23, pp. 427-432, 1998.

G. M. Orledge, “The identity of Leptothorax albipennis (Curtis) (Hymenoptera: Formicidae) and its presence in Great Britain”, Systematic Entomology, vol. 23, pp. 25-33, 1998.

J. Banaszak and Romasenko, L., Megachilid bees of Europe. Bydgoszcz: Pedagogical University of Bydgoszcz, 1998.

S. Foitzik and Heinze, J., “Nest site limitation and colony takeover in the ant Leptothorax nylanderi”, Behavioural Ecology, vol. 9, pp. 367-375, 1998.

N. A. Robinson, “Observations on the “guest ant” Formicoxenus nitidulus (Nylander) in nests of the red wood ant Formica rufa L. in 1997”, British Journal of Entomology and Natural History, vol. 11, pp. 125-128, 1998.