1. 3GPP. 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Architecture enhancements for non-3GPP accesses. Technical Specification 3G TS 23.402 Version 9.5.0 (2010-06), 2010.
2. 3GPP. 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Policy and charging control architecture. Technical Specification 3G TS 23.203 Version 9.5.0 (2010-06), 2010.
3. 3GPP. 3rd Generation Partnership Project; Technical Specification Group Service and System Aspects; Telecommunication management; Charging Management; IP Multimedia Subsystem (IMS) charging. Technical Specification 3G TS 32.260 Version 9.6.0 (2010-12), 2010.
4. 3GPP. 3rd Generation Partnership Project; Technical Specification Group Service and System Aspects; Telecommunication management; Charging management; Online Charging System (OCS): Applications and interfaces. Technical Specification 3G TS 32.296 Version 9.2.0 (2010-12), 2010.
5. 3GPP. 3rd Generation Partnership Project; Technical Specification Group Service and System Aspects; Telecommunication management; Charging management; Diameter charging applications. Technical Specification 3G TS 32.299 Version 9.6.0 (2010-12), 2010.