- Oddone, L. 2013
- Registro degli insetti impollinatori - Genere Ophrys. Available at: http://www.giros.it/forum/viewtopic.php?f=7&t=1497.
- Oertli, S., Müller, A. and Dorn, S. 2005
- Ecological and seasonal patterns in the diversity of a species-rich bee assemblage (Hymenoptera: Apoidea: Apiformes). European Journal of Entomology 102: 53–63.
- Ornosa, C. & Ortiz Sánchez, F.J. 2014
- Metadioxys graeca. The IUCN Red List of Threatened Species 2014: e.T19198293A21143845. Downloaded on 15 April 2019.
- Ornosa, C. & Ortiz-Sanchez, F.J. 2004
- Hymenoptera, Apoidea I. In M. A. e. a. Ramos (eds.), Fauna Ibérica. CSIC, Madrid, 556pp.
- Ortiz-Sánchez, F.J. 2006
- Advances in the knowledge of the Apoidea (Hymenoptera) of southern Spain, an area with a highly diversified fauna. Recent Research Developments in Entomology: 111-145.
- Ortiz-Sánchez, F.J. 2011
- Lista actualizada de las especies de abejas de España (Hymenoptera: Apoidea: Apiformes). Boletín de la Sociedad Entomológica Aragonesa 49: 265-281.
- Ortiz-Sanchez, F.J. & M. Terzo. 2004
- Sobre los Xylocopini ibéricos, con la primera cita de Xylocopa valga Gerstaecker 1872 para la fauna portuguesa y datos autoecológicos para Xylocopa cantabrita Lepeletier 1841 (Hymenoptera, Apoidea, Xylocopinae). Linzer biologische Beitrage, 36(1): 309-313.
- Ortiz-Sanchez, F.J., Ornosa, C. & Torres, F. 2012
- Especies ibéricas de los géneros Lithurgus Berthold, 1827, Creightonella Cockerell, 1908 y Chalicodoma Lepeletier, 1841 (Hymenoptera, Megachilidae): claves de identificación y nuevos datos de distribución. Graellsia 68: 181-206.
- Ortiz-Sánchez, F.J., Ornosa, C. and Kuhlmann, M. 2002
- Catálogo sinonímico de los Colletidae ibéricos. II, subfamilia Colletinae (Hymenoptera, Apoidea). Entomofauna 23: 267-278.
- Ortiz-Sanchez, J. & Pauly, A 2017
- Halictinae d'Espagne Belgian Journal of Entomology. 54: 1-92
- Osytshnjuk A.Z., Romasenko L., Banaszak J., Motyka E. 2008
- Andreninae of the Central and Eastern Palaearctic. Part 2. Annales de la Société entomologique de France (N.S.) 29 Vol. 5. Poznan: Polish Entomological Society; 233 p. ISBN 978-83-61607-11-3.
- Osytshnjuk AZ, Romasenko L, Banaszak J, Cierzniak T. 2005
- Andreninae of the Central and Eastern Palaearctic. Part 1. Vol. 2. Poznan: Polish Entomological Society; 235 p. ISBN 83-89-887-35-5.
- Osytshnjuk, A.Z. 1978
- Family Andrenidae. In: G.S. Medvedeva (ed.), The identification of the insects of the European part of the USSR, pp. 317-368.
- Osytshnjuk, A.Z. 1978
- [Colletidae, Andrenidae and Halictidae]. In: Medvedeva G.S. (ed.), The identification of the insects of the European part of the USSR] , pp. 279-415.
- Osytshnjuk, A.Z. 1983
- Three new species of the genus Andrena (Hymenoptera, Andrenidae) from Kazakhstan. Vestnik Zoologii (Kiev) 1: 20–27.
- Osytshnjuk, A.Z. 1977
- Fauna of the Ukraine. Vol 12 Bees [Apoidea]. No. 5. Family Andrenidae. Naukova Dumka, Kiev.
- Osytshnjuk, A.Z. 1986
- New Palaearctic species of the subgenus Euandrena Hed. (Hymenoptera, Andrenidae, Andrena F.). Entomology Obozrenie (Leningrad) 65(2): 407–418.
- Osytshnjuk, A.Z. 1967
- Bienen (Hymenoptera, Apoidea) die blüten auf dem wiesen im Gebirge und Hochgebirge der ukrainischen Karpaten bestäuben . Akademia Nauk. Proc. Zool. Inst. 38 : 366-381.
- Osytshnjuk, A.Z. 1995
- Family Andrenidae. In: P.A. Lehr (ed.), Keys to Insects of the Far East of Russia. Vol. 4. Megaloptera, Raphidioptera, Neuroptera, Mecoptera, Hymenoptera. Pt 1., pp. 606. St. Petersburg.
- Osytshnjuk, A.Z. 1994
- New Palaearctic subgenera and species of the genus Andrena (Hymenoptera, Andrenidae). Vestnik Zoologii 4: 17–23.
- Osytshnjuk, A.Z. 1977
- Fauna Ukraini Andrenidae (Apoidea, Andrenidae). Naukova Dumka, Kiev.
- Osytshnjuk, A.Z., Panfilov, D.V. and Ponomareva, A.A. 1978
- Superfamily Apoidea. In: Medvedev, G.S. (ed.), Key to the Insects of the European Part of the USSR., pp. 279–519 . Nauka. P., Leningrad.
- Osytshnjuk, A.Z., Romasenko, L., Banaszak, J. and Cierzniak, T. 2005
- Andreninae of the Central and Eastern Palaearctic. Part 1. Polish Entomological Monographs 2: 235.
- Osytshnjuk, A.Z., Romasenko, L., Banaszak, J. and Motyka, E. 2008
- Andreninae of the Central and Eastern Palaearctic. Part 2. Polish Entomological Society.
- Özbek, H. 2008
- Türkiye'de iliman iklim meyve türlerini ziyaret eden böcek türleri. . Uludağ Arıcılık Dergisi 8(3): 92-103.
- Özbek, H. 1976
- Bees of the family Andrenidae (Hymenoptera: Apoidea) in the Eastern Anatolia. Part I. Bitki Koruma Bülteni 16(3): 123-145.
- Özbek, H. 2010
- Doğu anadolu'nun bazi yörelerindekî Eucera Scop. ve Tetralonia Spin. (Anthophoridae: Hymenoptera) cînslerîne mensup arilar. Atatürk Üniversitesi Ziraat Fakültesi Dergisi/Journal of the Faculty of Agriculture 14: 35-40.
- O’Toole, C. 2010
- First British record of Megatoma undata (Linnaeus) (Dermestidae) from nests of the red mason bee, Osmia rufa (Linnaeus), with observations on larval behaviour. The Coleopterist 19(2): 65-73