diff --git a/pep-0418.txt b/pep-0418.txt
index eabd6c9df..2648264ef 100644
--- a/pep-0418.txt
+++ b/pep-0418.txt
@@ -201,6 +201,13 @@ CLOCK_MONOTONIC, CLOCK_MONOTONIC_RAW
 CLOCK_MONOTONIC and CLOCK_MONOTONIC_RAW represents monotonic time since some
 unspecified starting point. They cannot be set.
 
+Documentation: refer to the manual page of your operating system. Examples:
+
+ * `FreeBSD clock_gettime() manual page
+   <http://www.freebsd.org/cgi/man.cgi?query=clock_gettime>`_
+ * `Linux clock_gettime() manual page
+   <http://linux.die.net/man/3/clock_gettime>`_
+
 CLOCK_MONOTONIC is available at least on the following operating systems:
 
  * DragonFly BSD, FreeBSD >= 5.0, OpenBSD, NetBSD
@@ -237,11 +244,20 @@ Windows: QueryPerformanceCounter
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 High-resolution performance counter. It is monotonic.
-QueryPerformanceFrequency() gives its frequency. Hardward clocks used
-by QueryPerformanceCounter:
+QueryPerformanceFrequency() gives its frequency.
+
+Documentation:
+
+ * `MSDN: QueryPerformanceCounter() documentation
+   <http://msdn.microsoft.com/en-us/library/windows/desktop/ms644904%28v=vs.85%29.aspx>`_
+ * `MSDN: QueryPerformanceFrequency() documentation
+   <http://msdn.microsoft.com/en-us/library/windows/desktop/ms644905%28v=vs.85%29.aspx>`_
+
+Hardware clocks used by QueryPerformanceCounter:
 
  * Windows XP: RDTSC instruction of Intel processors, the clock frequency is
-   the frequency of the processor
+   the frequency of the processor (between 200 MHz and 3 GHz, usually greater
+   than 1 GHz nowadays)
  * Windows 2000: ACPI power management timer, frequency = 3,549,545 Hz
  * Windows 95/98: 8245 PIT chipset, frequency = 1,193,181 Hz