Hawkinson, J. and T. Bates, "Guidelines for creation, selection, and registration of an Autonomous System (AS)", BCP 6, RFC 1930, March 1996. 

Mitchell, J., "Autonomous System (AS) Reservation for Private Use", BCP 6, RFC 6996, July 2013.

Haas, J. and J. Mitchell, "Reservation of Last Autonomous System (AS) Numbers", BCP 6, RFC 7300, July 2014.

<https://www.rfc-editor.org/info/bcp6>