(en) Gottimukula PraveenReddy1, Imteyaz Ahmad, Killedar Pankaj Damodar et Anjaneyulu K V V S S S R, « Study of Data Relay Satellite Systemand its Relevance to Indian context », International Journal of Pure and Applied Mathematics, vol. 118, no 16, , p. 1227-1244 (lire en ligne)