Steppe: a biome (or subdivision of the Earth’s surface) that is composed of a swathe of temperate grassland stretching from Romania to China.
Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
Mallon, D.P. and Kingswood, S.C. (2001) Global Survey and Regional Action Plans - Antelopes. Part 4: North Africa, the Middle East and Asia.IUCN, Gland, Switzerland.
Beudels, R.C., Devilliers, P., Lafontaine, R., Devilliers-Terschuren, J. and Beudels, M. (2006) CMS SSA Concerted Action. 2d Edition. CMS Technical Series Publication No. 10.UNEP/CMS Secretariat, Bonn, Germany.
Groves, C.P. (1996) Taxonomic Diversity in Arabian Gazelles: The State of the Art. In: Greth, A., Magin, C. and and Ancrenaz, M. (Eds) Conservation of Arabian Gazelles.National Commission for Wildlife Conservation and Development, Riyadh. Available at: http://arts.anu.edu.au/grovco/Conservation%20Arabian%20gazelles.pdf