diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index 8aaecf0e..b1c09412 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -313,7 +313,7 @@ namespace WebSocketSharp
     internal static void CloseWithAuthChallenge (
       this HttpListenerResponse response, string challenge)
     {
-      response.Headers.SetInternal ("WWW-Authenticate", challenge, true);
+      response.Headers.SetInternally ("WWW-Authenticate", challenge, true);
       response.Close (HttpStatusCode.Unauthorized);
     }
 
diff --git a/websocket-sharp/HandshakeRequest.cs b/websocket-sharp/HandshakeRequest.cs
index 79ecfee4..92d90776 100644
--- a/websocket-sharp/HandshakeRequest.cs
+++ b/websocket-sharp/HandshakeRequest.cs
@@ -162,7 +162,7 @@ namespace WebSocketSharp
 
       var headers = new WebHeaderCollection ();
       for (int i = 1; i < headerParts.Length; i++)
-        headers.SetInternal (headerParts [i], false);
+        headers.SetInternally (headerParts [i], false);
 
       return new HandshakeRequest {
         Headers = headers,
diff --git a/websocket-sharp/HandshakeResponse.cs b/websocket-sharp/HandshakeResponse.cs
index a52a64fc..de7e6bc7 100644
--- a/websocket-sharp/HandshakeResponse.cs
+++ b/websocket-sharp/HandshakeResponse.cs
@@ -140,7 +140,7 @@ namespace WebSocketSharp
 
       var headers = new WebHeaderCollection ();
       for (int i = 1; i < headerParts.Length; i++)
-        headers.SetInternal (headerParts [i], true);
+        headers.SetInternally (headerParts [i], true);
 
       return new HandshakeResponse {
         Headers = headers,
diff --git a/websocket-sharp/Net/HttpListenerRequest.cs b/websocket-sharp/Net/HttpListenerRequest.cs
index ad36028b..282b1200 100644
--- a/websocket-sharp/Net/HttpListenerRequest.cs
+++ b/websocket-sharp/Net/HttpListenerRequest.cs
@@ -527,7 +527,7 @@ namespace WebSocketSharp.Net
       var name = header.Substring (0, colon).Trim ();
       var val = header.Substring (colon + 1).Trim ();
       var lower = name.ToLower (CultureInfo.InvariantCulture);
-      _headers.SetInternal (name, val, false);
+      _headers.SetInternally (name, val, false);
 
       if (lower == "accept") {
         _acceptTypes = val.SplitHeaderValue (',').ToArray ();
diff --git a/websocket-sharp/Net/HttpListenerResponse.cs b/websocket-sharp/Net/HttpListenerResponse.cs
index 68ec1c33..5e8d8fa5 100644
--- a/websocket-sharp/Net/HttpListenerResponse.cs
+++ b/websocket-sharp/Net/HttpListenerResponse.cs
@@ -538,20 +538,20 @@ namespace WebSocketSharp.Net
         if (_contentEncoding != null &&
             _contentType.IndexOf ("charset=", StringComparison.Ordinal) == -1) {
           var charset = _contentEncoding.WebName;
-          _headers.SetInternal (
+          _headers.SetInternally (
             "Content-Type", _contentType + "; charset=" + charset, true);
         }
         else {
-          _headers.SetInternal ("Content-Type", _contentType, true);
+          _headers.SetInternally ("Content-Type", _contentType, true);
         }
       }
 
       if (_headers ["Server"] == null)
-        _headers.SetInternal ("Server", "websocket-sharp/1.0", true);
+        _headers.SetInternally ("Server", "websocket-sharp/1.0", true);
 
       var provider = CultureInfo.InvariantCulture;
       if (_headers ["Date"] == null)
-        _headers.SetInternal (
+        _headers.SetInternally (
           "Date", DateTime.UtcNow.ToString ("r", provider), true);
 
       if (!_chunked) {
@@ -561,7 +561,7 @@ namespace WebSocketSharp.Net
         }
 
         if (_contentLengthSet)
-          _headers.SetInternal (
+          _headers.SetInternally (
             "Content-Length", _contentLength.ToString (provider), true);
       }
 
@@ -591,36 +591,36 @@ namespace WebSocketSharp.Net
 
       // They sent both KeepAlive: true and Connection: close!?
       if (!_keepAlive || connClose) {
-        _headers.SetInternal ("Connection", "close", true);
+        _headers.SetInternally ("Connection", "close", true);
         connClose = true;
       }
 
       if (_chunked)
-        _headers.SetInternal ("Transfer-Encoding", "chunked", true);
+        _headers.SetInternally ("Transfer-Encoding", "chunked", true);
 
       int reuses = _context.Connection.Reuses;
       if (reuses >= 100) {
         _forceCloseChunked = true;
         if (!connClose) {
-          _headers.SetInternal ("Connection", "close", true);
+          _headers.SetInternally ("Connection", "close", true);
           connClose = true;
         }
       }
 
       if (!connClose) {
-        _headers.SetInternal (
+        _headers.SetInternally (
           "Keep-Alive",
           String.Format ("timeout=15,max={0}", 100 - reuses), true);
         if (_context.Request.ProtocolVersion <= HttpVersion.Version10)
-          _headers.SetInternal ("Connection", "keep-alive", true);
+          _headers.SetInternally ("Connection", "keep-alive", true);
       }
 
       if (_location != null)
-        _headers.SetInternal ("Location", _location, true);
+        _headers.SetInternally ("Location", _location, true);
 
       if (_cookies != null) {
         foreach (Cookie cookie in _cookies)
-          _headers.SetInternal ("Set-Cookie", cookie.ToResponseString (), true);
+          _headers.SetInternally ("Set-Cookie", cookie.ToResponseString (), true);
       }
 
       var encoding = _contentEncoding ?? Encoding.Default;
diff --git a/websocket-sharp/Net/WebHeaderCollection.cs b/websocket-sharp/Net/WebHeaderCollection.cs
index ebf7242a..f328f935 100644
--- a/websocket-sharp/Net/WebHeaderCollection.cs
+++ b/websocket-sharp/Net/WebHeaderCollection.cs
@@ -886,18 +886,18 @@ namespace WebSocketSharp.Net
       return info != null && info.IsMultiValue (response);
     }
 
-    internal void RemoveInternal (string name)
+    internal void RemoveInternally (string name)
     {
       base.Remove (name);
     }
 
-    internal void SetInternal (string header, bool response)
+    internal void SetInternally (string header, bool response)
     {
       var pos = checkColonSeparated (header);
-      SetInternal (header.Substring (0, pos), header.Substring (pos + 1), response);
+      SetInternally (header.Substring (0, pos), header.Substring (pos + 1), response);
     }
 
-    internal void SetInternal (string name, string value, bool response)
+    internal void SetInternally (string name, string value, bool response)
     {
       value = checkValue (value);
       if (IsMultiValue (name, response))
@@ -1124,6 +1124,9 @@ namespace WebSocketSharp.Net
     /// <param name="index">
     /// An <see cref="int"/> that represents the zero-based index of the header to find.
     /// </param>
+    /// <exception cref="ArgumentOutOfRangeException">
+    /// <paramref name="index"/> is out of allowable range of indexes for the collection.
+    /// </exception>
     public override string Get (int index)
     {
       return base.Get (index);
@@ -1133,8 +1136,8 @@ namespace WebSocketSharp.Net
     /// Get the value of the header with the specified <paramref name="name"/> in the collection.
     /// </summary>
     /// <returns>
-    /// A <see cref="string"/> that receives the value of the header. <see langword="null"/> if
-    /// there is no header with <paramref name="name"/> in the collection.
+    /// A <see cref="string"/> that receives the value of the header if found; otherwise,
+    /// <see langword="null"/>.
     /// </returns>
     /// <param name="name">
     /// A <see cref="string"/> that represents the name of the header to find.
@@ -1165,21 +1168,28 @@ namespace WebSocketSharp.Net
     /// <param name="index">
     /// An <see cref="int"/> that represents the zero-based index of the header to find.
     /// </param>
+    /// <exception cref="ArgumentOutOfRangeException">
+    /// <paramref name="index"/> is out of allowable range of indexes for the collection.
+    /// </exception>
     public override string GetKey (int index)
     {
       return base.GetKey (index);
     }
 
     /// <summary>
-    /// Gets an array of header values stored in the specified <paramref name="index"/> position of
-    /// the collection.
+    /// Gets an array of header values stored in the specified <paramref name="index"/> position
+    /// of the collection.
     /// </summary>
     /// <returns>
-    /// An array of <see cref="string"/> that receives the header values.
+    /// An array of <see cref="string"/> that receives the header values if found; otherwise,
+    /// <see langword="null"/>.
     /// </returns>
     /// <param name="index">
     /// An <see cref="int"/> that represents the zero-based index of the header to find.
     /// </param>
+    /// <exception cref="ArgumentOutOfRangeException">
+    /// <paramref name="index"/> is out of allowable range of indexes for the collection.
+    /// </exception>
     public override string [] GetValues (int index)
     {
       var values = base.GetValues (index);
@@ -1192,7 +1202,8 @@ namespace WebSocketSharp.Net
     /// Gets an array of header values stored in the specified <paramref name="header"/>.
     /// </summary>
     /// <returns>
-    /// An array of <see cref="string"/> that receives the header values.
+    /// An array of <see cref="string"/> that receives the header values if found; otherwise,
+    /// <see langword="null"/>.
     /// </returns>
     /// <param name="header">
     /// A <see cref="string"/> that represents the name of the header to find.