diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index 28167466..4bf2a135 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -475,6 +475,28 @@ namespace WebSocketSharp
       return nameAndValue.GetValue (separator, false);
     }
 
+    /// <summary>
+    /// Gets the value from the specified string that contains a pair of
+    /// name and value separated by a character.
+    /// </summary>
+    /// <returns>
+    ///   <para>
+    ///   A <see cref="string"/> that represents the value.
+    ///   </para>
+    ///   <para>
+    ///   <see langword="null"/> if the value is not present.
+    ///   </para>
+    /// </returns>
+    /// <param name="nameAndValue">
+    /// A <see cref="string"/> that contains a pair of name and value.
+    /// </param>
+    /// <param name="separator">
+    /// A <see cref="char"/> used to separate name and value.
+    /// </param>
+    /// <param name="unquote">
+    /// A <see cref="bool"/>: <c>true</c> if unquotes the value; otherwise,
+    /// <c>false</c>.
+    /// </param>
     internal static string GetValue (
       this string nameAndValue, char separator, bool unquote
     )