BirdLife International. 2019. Aquila heliaca (amended version of 2017 assessment). The IUCN Red List of Threatened Species 2019: e.T22696048A155464885. doi:10.2305/IUCN.UK.2019-3.RLTS.T22696048A155464885.en, Downloaded on 05 May 2020.
UNEP (2020). Aquila heliaca. The Species+ Website. Nairobi, Kenya. Compiled by UNEP-WCMC, Cambridge, UK. Available at: www.speciesplus.net. (downroad 05/05/2020)