Radonjic, V., A. K. Ljubisavljevic, and M. Stojanovic. “Quality of Experience and Users Elasticity Considerations for Modelling Competition Between Service Providers in NGN”. Elektronika Ir Elektrotechnika, vol. 18, no. 8, Oct. 2012, pp. 113-6, doi:10.5755/j01.eee.18.8.2640.