1. Ahlén I. 1981 Identification of Scandinavian bats by their sounds. Uppsala: The Swedish University of Agricultural Sciences Department of Wildlife Ecology.
2. Aubauer R. 1994 Dreidimensionale Flugbahnverfolgung von Fledermäusen Fortschritte der Akustik-DAGA 94. Bad Honnef Germany: DPG-GmbH.
3. Aubauer R. & Ruppert C. 1994 Untersuchung von Mikrofonanordnungen zur passiven Ortung von Schallquellen Fortschritte der Akustik-DAGA 94. Bad Honnef Germany: DPGGmbH.
4. Sound absorption in air at frequencies up to 100 kHz;Bazley E. N.;NPL Acoustics Report Ac,1976
5. Frequency sensitivity and directional hearing in the gleaning bat,Plecotus auritus (Linnaeus 1758)