Obrist, M.K., Duelli, P. (1996): Trapping efficiency of funnel- and cup-traps for epigeal arthropods. Mitteilungen der Schweizerischen entomologischen Gesellschaft, 69: 361-369.
Obrtel, R. (1971): Number of pitfall traps in relation to the structure of the catch of soil surface Coleoptera. Acta ent. bohemoslov., 68: 300-309.
Obrtel, R. (1971): Soil surface Coleoptera in a lowland forest. Acta Sc. Nat. Brno, 5: 1-47.
Obrtel, R. (1973):Animal food of Apodemus flavicollis in a lowland forest. Zoologické Listy, 22: 15-30.
Obrtel, R. (1973): Animal food of Clethrionomys glareolus in a lowland forest. Zoologické Listy, 22: 111-126.
Obrtel, R. (1976): Soil surface harvestmen (Opilionidea) in a lowland forest. Acta Sc. Nat. Brno, 10: 1-34.
Obrtel, R., Holišová, V. (1981): The diet of hedgehogs in a urban environment. Folia Zologica, 30: 193-201.
Ochoa, J.A., Acosta, L.E. (2002):Two new Andean species of Brachistosternus Pocock (Scorpiones: Bothriuridae). Euscorpius, 2: 1–12.