* Wink, M.; Sauer-Gürth, H.; Ellis, D. & Kenward, R. (2004): Phylogenetic relationships in the Hierofalco complex (Saker-, Gyr-, Lanner-, Laggar Falcon).
* Wink, M.; Sauer-Gürth, H.; Ellis, D. & Kenward, R. (2004): Phylogenetic relationships in the Hierofalco complex (Saker-, Gyr-, Lanner-, Laggar Falcon).