1421, IAB IRTF PSRG, IETF PEM WG, February 1993.

   [RFC-1154] Robinson, D. and R. Ullmann, "Encoding Header Field for
   Internet Messages", RFC 1154, Prime Computer, Inc., April 1990.

   [RFC-1341] Borenstein, N., and N.  Freed, "MIME (Multipurpose Internet
   Mail Extensions): Mechanisms for Specifying and Describing the Format
   of Internet Message Bodies", RFC 1341, Bellcore, Innosoft, June 1992.

   [RFC-1342] Moore, K., "Representation of Non-Ascii Text in Internet
   Message Headers", RFC 1342, University of Tennessee, June 1992.

   [RFC-1343] Borenstein, N., "A User Agent Configuration Mechanism
   for Multimedia Mail Format Information", RFC 1343, Bellcore, June
   1992.

   [RFC-1344] Borenstein, N., "Implications of MIME for Internet
   Mail Gateways", RFC 1344, Bellcore, June 1992.

   [RFC-1345] Simonsen, K., "Character Mnemonics & Character Sets",
   RFC 1345, Rationel Almen Planlaegning, June 1992.

   [RFC-1426] Klensin, J., (WG Chair), Freed, N., (Editor), Rose, M.,
   Stefferud, E., and D. Crocker, "SMTP Service Extension for 8bit-MIME
   transport", RFC 1426, United Nations Universit, Innosoft, Dover Beach
   Consulting, Inc., Network Management Associates, Inc., The Branch
   Office, February 1993.

   [RFC-1522] Moore, K., "Representation of Non-Ascii Text in Internet
   Message Headers" RFC 1522, University of Tennessee, September 1993.

   [RFC-1340] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC
   1340, USC/Information Sciences Institute, July 1992.