diff --git a/websocket-sharp/Net/WebHeaderCollection.cs b/websocket-sharp/Net/WebHeaderCollection.cs
index c083a2dd..5d0baaf7 100644
--- a/websocket-sharp/Net/WebHeaderCollection.cs
+++ b/websocket-sharp/Net/WebHeaderCollection.cs
@@ -1122,12 +1122,16 @@ namespace WebSocketSharp.Net
     }
 
     /// <summary>
-    /// Adds the specified request <paramref name="header"/> with
-    /// the specified <paramref name="value"/> to the collection.
+    /// Adds the specified request header with the specified value to
+    /// the collection.
     /// </summary>
     /// <param name="header">
-    /// One of the <see cref="HttpRequestHeader"/> enum values, represents
-    /// the request header to add.
+    ///   <para>
+    ///   One of the <see cref="HttpRequestHeader"/> enum values.
+    ///   </para>
+    ///   <para>
+    ///   It represents the request header to add.
+    ///   </para>
     /// </param>
     /// <param name="value">
     /// A <see cref="string"/> that represents the value of the header to add.
@@ -1140,15 +1144,15 @@ namespace WebSocketSharp.Net
     ///   -or-
     ///   </para>
     ///   <para>
-    ///   <paramref name="value"/> contains invalid characters.
+    ///   <paramref name="value"/> contains an invalid character.
     ///   </para>
     /// </exception>
     /// <exception cref="ArgumentOutOfRangeException">
-    /// The length of <paramref name="value"/> is greater than 65,535 characters.
+    /// The length of <paramref name="value"/> is greater than 65,535
+    /// characters.
     /// </exception>
     /// <exception cref="InvalidOperationException">
-    /// The current <see cref="WebHeaderCollection"/> instance doesn't allow
-    /// the request <paramref name="header"/>.
+    /// This instance does not allow the request header.
     /// </exception>
     public void Add (HttpRequestHeader header, string value)
     {