--- a/discussion.roff	Thu Jul 12 00:56:47 2012 +0200
+++ b/discussion.roff	Thu Jul 12 01:07:44 2012 +0200
@@ -217,10 +217,7 @@
 separate projects then they should be separated.
 In my opinion, this is the case here.
 The RFCs propose this separation by clearly distinguishing the different
-mail handling tasks.
-.[
-rfc 821
-.]
+mail handling tasks [RFC\|821].
 The small interfaces between the mail agents support the separation.
 .P
 Email once had been small and simple.
@@ -1351,10 +1348,7 @@
 .Sw -[no]check
 switches were removed together with the support for
 .Hd Content-MD5
-header fields.
-.[
-rfc 1864
-.]
+header fields [RFC\|1864].
 .Ci 31dc797eb5178970d68962ca8939da3fd9a8efda
 (cf. Sec.
 .Cf content-md5 )
@@ -1928,7 +1922,7 @@
 .H2 "Attachments
 .P
 The mind model of email attachments is unrelated to MIME.
-Although the MIME RFCs (2045 through 2049) define the technical
+Although the MIME RFCs [RFC\|2045\(enRFC\|2049] define the technical
 requirements for having attachments, they do not mention the word
 attachment.
 Instead of attachments, MIME talks about ``multi-part message bodies''

--- a/preface.roff	Thu Jul 12 00:56:47 2012 +0200
+++ b/preface.roff	Thu Jul 12 01:07:44 2012 +0200
@@ -173,7 +173,7 @@
 The reader is expected to know the format of email messages and
 the structure of email transfer systems, at least on a basic level.
 It's advisable to have cross-read RFC\|821 and RFC\|822.
-Furthermore, basic understanding of MIME (RFC\|2045\(en2049)
+Furthermore, basic understanding of MIME [RFC\|2045\(enRFC\|2049]
 is good to have.
 The Wikipedia provides good introduction-level information about email.
 .[
@@ -248,7 +248,7 @@
 .Pn cat ,
 which is in section one of the Unix manual.
 Internet technologies are specified by \fIRequests for Comments\fP (RFCs).
-Throughout the document, they are referenced as ``RFC\|821''.
+Throughout the document, they are referenced similar to ``RFC\|821''.
 A list of relevant RFCs is located at the end of the document.
 Literature is cited in backets, such as
 .[ ``[

--- a/rfcs.roff	Thu Jul 12 00:56:47 2012 +0200
+++ b/rfcs.roff	Thu Jul 12 01:07:44 2012 +0200
@@ -23,6 +23,10 @@
 .I "Standard for the Format of ARPA Internet Text Messages",
 August 1982.
 
+.IP RFC\|1864
+.I "The Content-MD5 Header Field",
+October 1995.
+
 .IP RFC\|2045
 .I "Multipurpose Internet Mail Extensions (MIME) Part One:\
 	Format of Internet Message Bodies" ,
@@ -47,3 +51,15 @@
 	Conformance Criteria and Examples" ,
 November 1996.
 
+.IP RFC\|2822
+.I "Internet Message Format",
+April 2001.
+
+.IP RFC\|3156
+.I "MIME Security with OpenPGP",
+August 2001.
+
+.IP RFC\|4880
+.I "OpenPGP Message Format",
+November 2007.
+