IEEE Computer Society, "IEEE Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (LR-WPANs); September 8 2006, http://standards.ieee.org/getieee802/download/802.15.4-2006.pdf

IEEE Computer Society, "IEEE Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (LR-WPANs); October 1, 2003, http://standards.ieee.org/getieee802/download/802.15.4-2003.pdf

How to become an IEEE 802.15.4 expert, http://www.IEEE802.org/15/pub/TG4Expert.html