diff --git a/INSTALL b/INSTALL
index 8184235..a2b4036 100644
--- a/INSTALL
+++ b/INSTALL
@@ -39,10 +39,11 @@ with line editing support.  If you don't want this, specify the
 --disable-readline flag to configure.  Please refer to the chrony.txt
 file for more information.
 
-If a `timepps.h' header is available, chronyd will be built with PPS
-API reference clock driver.  If the header is installed in a location
-that isn't normally searched by the compiler, you can add it to the
-searched locations by setting CPPFLAGS variable to -I/path/to/timepps.
+If a 'timepps.h' header is available (e.g. from the LinuxPPS project
+(http://linuxpps.org/)), chronyd will be built with PPS API reference
+clock driver.  If the header is installed in a location that isn't
+normally searched by the compiler, you can add it to the searched
+locations by setting 'CPPFLAGS' variable to '-I/path/to/timepps'.
 
 Now type
 
diff --git a/chrony.texi.in b/chrony.texi.in
index e455810..09740b9 100644
--- a/chrony.texi.in
+++ b/chrony.texi.in
@@ -391,7 +391,8 @@ If editline or readline library is available, chronyc will be built with line
 editing support.  If you don't want this, specify the --disable-readline flag
 to configure.  Please refer to @pxref{line editing support} for more information.
 
-If a @file{timepps.h} header is available, chronyd will be built with PPS API
+If a @file{timepps.h} header is available (e.g. from the
+@uref{http://linuxpps.org/, LinuxPPS project}), chronyd will be built with PPS API
 reference clock driver.  If the header is installed in a location that isn't
 normally searched by the compiler, you can add it to the searched locations by
 setting @code{CPPFLAGS} variable to @code{-I/path/to/timepps}.
@@ -2493,8 +2494,9 @@ A driver option in form @code{:perm=NNN} can be appended to the
 segment number to create the segment with permissions other than the
 default @code{0600}. 
 
-Some examples of applications that can be used as SHM sources are @code{gpsd},
-@code{shmpps} and @code{radioclk}.
+Some examples of applications that can be used as SHM sources are
+@uref{http://catb.org/gpsd/, @code{gpsd}}, @code{shmpps} and
+@uref{http://www.buzzard.me.uk/jonathan/radioclock.html, @code{radioclk}}.
 @item SOCK
 Unix domain socket driver.  It is similar to the SHM driver, but uses a
 different format and uses a socket instead of shared memory.  It does not