diff --git a/man2/intro.2 b/man2/intro.2
index d86fecba7..06618bb41 100644
--- a/man2/intro.2
+++ b/man2/intro.2
@@ -175,7 +175,7 @@ SVID
 System V Interface Definition, as described in "The System V Interface
 Definition, Fourth Edition".
 .TP
-POSIX.1
+POSIX.1-1990
 IEEE 1003.1-1990 part 1, aka ISO/IEC 9945-1:1990s, aka "IEEE Portable
 Operating System Interface for Computing Environments", as elucidated
 in Donald Lewine's "POSIX Programmer's Guide" (O'Reilly & Associates,
@@ -187,11 +187,38 @@ for portable operating systems, aka ISO/IEC 9945-1:1996, as elucidated in
 "Programming for the real world \- POSIX.4"
 by Bill O. Gallmeister (O'Reilly & Associates, Inc. ISBN 1-56592-074-0).
 .TP
+POSIX.1c
+IEEE Std 1003.1c-1995 describing the POSIX threads interfaces.
+.TP
+POSIX.1-1996
+A 1996 revision of POSIX.1 which incorporated POSIX.1b and POSIX.1c.
+.TP
 SUS, SUSv2
 Single Unix Specification.
 (Developed by X/Open and The Open Group. See also
 http://www.UNIX-systems.org/version2/ .)
 .TP
+POSIX.1-2001, SUSv3
+The 2001 revision and consolidation of the POSIX.1 and SUS standards
+into a single document, conducted under the auspices of the Austin group
+(http://www.opengroup.org/austin/ .)  
+The standard is available online at 
+http://www.unix-systems.org/version3/ , 
+and the interfaces that it describes are also available in the Linux 
+manual pages package under sections 1p and 3p (e.g., "man 3p open").
+The standard defines two levels of conformance: 
+.IR "POSIX conformance" ,
+which is a baseline set of interfaces required of a conforming system; 
+and
+.IR "XSI Conformance", 
+which additionally mandates a set of interfaces
+(the "XSI extension") which are only optional for POSIX conformance.  
+XSI-conformant systems can be branded
+.IR "UNIX 03" .
+Two Technical Corrigenda (minor fixes and improvements) 
+of the original 2001 standard have occurred:
+TC1 in 2003, and TC2 in 2004.
+.TP
 4.3BSD/4.4BSD
 The 4.3 and 4.4 distributions of Berkeley Unix.  4.4BSD was
 upward-compatible from 4.3.