509 Internet Public Key Infrastructure Online Certificate Status Protocol - OCSP. M. Myers, R. Ankney, A. Malpani, S. Galperin, C. Adams. June 1999. http://www.faqs.org/rfcs/rfc2560.html
Internet Printing Protocol/1.0: Encoding and Transport. R. Herriot, Ed., S. Butler, P. Moore, R. Turner. April 1999. http://www.faqs.org/rfcs/rfc2565.html
Neda's Efficient Mail Submission and Delivery (EMSD) Protocol Specification Version 1.3. M. Banan. February 1999. http://www.faqs.org/rfcs/rfc2524.html