diff --git a/pkgs/development/interpreters/erlang/R14B04.nix b/pkgs/development/interpreters/erlang/R14B04.nix
index b5133bd7f83..5b143ffefc5 100644
--- a/pkgs/development/interpreters/erlang/R14B04.nix
+++ b/pkgs/development/interpreters/erlang/R14B04.nix
@@ -1,23 +1,23 @@
 { stdenv, fetchurl, perl, gnum4, ncurses, openssl }:
 
-let version = "R14B04"; in
+let version = "14B04"; in
 
 stdenv.mkDerivation {
   name = "erlang-" + version;
-  
+
   src = fetchurl {
-    url = "http://www.erlang.org/download/otp_src_" + version + ".tar.gz";
+    url = "http://www.erlang.org/download/otp_src_R${version}.tar.gz";
     sha256 = "0vlvjlg8vzcy6inb4vj00bnj0aarvpchzxwhmi492nv31s8kb6q9";
   };
-  
+
   buildInputs = [ perl gnum4 ncurses openssl ];
-  
+
   patchPhase = '' sed -i "s@/bin/rm@rm@" lib/odbc/configure erts/configure '';
-  
+
   preConfigure = ''
     export HOME=$PWD/../
     sed -e s@/bin/pwd@pwd@g -i otp_build
   '';
-  
+
   configureFlags = "--with-ssl=${openssl}";
 }
diff --git a/pkgs/development/interpreters/erlang/R15B02.nix b/pkgs/development/interpreters/erlang/R15B02.nix
index 50d818e1bb1..05ec1013460 100644
--- a/pkgs/development/interpreters/erlang/R15B02.nix
+++ b/pkgs/development/interpreters/erlang/R15B02.nix
@@ -3,26 +3,26 @@
 
 assert wxSupport -> mesa != null && wxGTK != null && xlibs != null;
 
-let version = "R15B02"; in
+let version = "15B02"; in
 
 stdenv.mkDerivation {
   name = "erlang-" + version;
-  
+
   src = fetchurl {
-    url = "http://www.erlang.org/download/otp_src_" + version + ".tar.gz";
+    url = "http://www.erlang.org/download/otp_src_R{version}.tar.gz";
     sha256 = "03eb0bd640916666ff83df1330912225fbf555e0c8cf58bb35d8307a314f1158";
   };
-  
-  buildInputs = 
+
+  buildInputs =
     [ perl gnum4 ncurses openssl
     ] ++ stdenv.lib.optional wxSupport [ mesa wxGTK xlibs.libX11 ];
-  
+
   patchPhase = '' sed -i "s@/bin/rm@rm@" lib/odbc/configure erts/configure '';
-  
+
   preConfigure = ''
     export HOME=$PWD/../
     sed -e s@/bin/pwd@pwd@g -i otp_build
   '';
-  
+
   configureFlags = "--with-ssl=${openssl}";
 }