diff --git a/compiler/res/prog8lib/c64/graphics.p8 b/compiler/res/prog8lib/c64/graphics.p8
index 30331abf5..40ed81637 100644
--- a/compiler/res/prog8lib/c64/graphics.p8
+++ b/compiler/res/prog8lib/c64/graphics.p8
@@ -33,10 +33,10 @@ graphics {
 
     sub line(uword @zp x1, ubyte @zp y1, uword @zp x2, ubyte @zp y2) {
         ; Bresenham algorithm.
-        ; This code special cases various quadrant loops to allow simple ++ and -- operations.
+        ; This code special-cases various quadrant loops to allow simple ++ and -- operations.
         ; TODO rewrite this in optimized assembly
         if y1>y2 {
-            ; make sure dy is always positive to avoid 8 instead of just 4 special cases
+            ; make sure dy is always positive to have only 4 instead of 8 special cases
             swap(x1, x2)
             swap(y1, y2)
         }
diff --git a/docs/source/libraries.rst b/docs/source/libraries.rst
index 6a4595a43..6ccc617bb 100644
--- a/docs/source/libraries.rst
+++ b/docs/source/libraries.rst
@@ -16,6 +16,10 @@ with Prog8 are written like this.
 You can ``%import`` and use these modules explicitly, but the compiler may also import one or more
 of these library modules automatically as required.
 
+For full details on what is available in the libraries, look at their source code here:
+https://github.com/irmen/prog8/tree/master/compiler/res/prog8lib
+
+
 .. caution::
     The resulting compiled binary program *only works on the target machine it was compiled for*.
     You must recompile the program for every target you want to run it on.