1. IEEE C95.1-1999, Safety levels with respect to human exposure to radio frequency electromagnetic fields: 3 kHz to 300 GHz, IEEE standard, 1999.
2. Office of the Telecommunications Authority, HKSAR, http://www.ofta.gov.hk/tec/information-notes/in42303.html.
3. EN50361:2001, Basic standard for the measurement of specific absorption rate related to human exposure to electromagnetic fields from mobile phones (300 MHz-3 GHz), European Standard, 2001.