diff --git a/rtl/i386/math.inc b/rtl/i386/math.inc
index ac8f420d8d..b56c3aa3e3 100644
--- a/rtl/i386/math.inc
+++ b/rtl/i386/math.inc
@@ -111,6 +111,7 @@
     end;
 
   {$define FPC_SYSTEM_HAS_EXP}
+    { exp function adapted from AMath library (C) Copyright 2009-2013 Wolfgang Ehrhardt }
     function fpc_exp_real(d : ValReal) : ValReal;assembler;compilerproc;
       asm
         fldt        d
diff --git a/rtl/inc/genmath.inc b/rtl/inc/genmath.inc
index f20887edd6..935dc8736d 100644
--- a/rtl/inc/genmath.inc
+++ b/rtl/inc/genmath.inc
@@ -368,6 +368,7 @@ type
 
 {$ifndef SYSTEM_HAS_LDEXP}
 {$ifdef SUPPORT_DOUBLE}
+{ ldexpd function adapted from DAMath library (C) Copyright 2013 Wolfgang Ehrhardt }
     function ldexp( x: Real; N: Integer):Real;
     {* ldexp() multiplies x by 2**n.                                    *}
     var
diff --git a/rtl/objpas/math.pp b/rtl/objpas/math.pp
index 11c0dec13e..4259b88413 100644
--- a/rtl/objpas/math.pp
+++ b/rtl/objpas/math.pp
@@ -783,7 +783,7 @@ begin
   csc := cosecant(x);
 end;
 
-
+{ arcsin and arccos functions from AMath library (C) Copyright 2009-2013 Wolfgang Ehrhardt }
 function arcsin(x : float) : float;
 begin
   arcsin:=arctan2(x,sqrt((1.0-x)*(1.0+x)));
@@ -881,6 +881,7 @@ function artanh(x : float) : float;
     artanh:=(lnxp1(x)-lnxp1(-x))*0.5;
   end;
 
+{ hypot function from AMath library (C) Copyright 2009-2013 Wolfgang Ehrhardt }
 function hypot(x,y : float) : float;
   begin
     x:=abs(x);
@@ -910,6 +911,7 @@ function logn(n,x : float) : float;
      logn:=ln(x)/ln(n);
   end;
 
+{ lnxp1 function from AMath library (C) Copyright 2009-2013 Wolfgang Ehrhardt }
 function lnxp1(x : float) : float;
   var
     y: float;