diff --git a/BurnOutSharp/FileType/MicrosoftCAB.cs b/BurnOutSharp/FileType/MicrosoftCAB.cs
index f0cdb230..dff92bac 100644
--- a/BurnOutSharp/FileType/MicrosoftCAB.cs
+++ b/BurnOutSharp/FileType/MicrosoftCAB.cs
@@ -7,6 +7,7 @@ using LibMSPackN;
 
 namespace BurnOutSharp.FileType
 {
+    // Specification available at http://download.microsoft.com/download/5/0/1/501ED102-E53F-4CE0-AA6B-B0F93629DDC6/Exchange/%5BMS-CAB%5D.pdf
     internal class MicrosoftCAB
     {
         public static bool ShouldScan(byte[] magic)