diff --git a/MangaRipper.Core/Helper/ChapterProgress.cs b/MangaRipper.Core/Helper/ChapterProgress.cs
deleted file mode 100644
index 42233a2..0000000
--- a/MangaRipper.Core/Helper/ChapterProgress.cs
+++ /dev/null
@@ -1,22 +0,0 @@
-namespace MangaRipper.Core
-{
-    public class ChapterProgress
-    {
-        public ChapterProgress(Chapter chapter, int percent)
-        {
-            Chapter = chapter;
-            Percent = percent;
-        }
-        public Chapter Chapter
-        {
-            get;
-            private set;
-        }
-
-        public int Percent
-        {
-            get;
-            private set;
-        }
-    }
-}
diff --git a/MangaRipper.Core/MangaRipper.Core.csproj b/MangaRipper.Core/MangaRipper.Core.csproj
index 5d0bc58..90fbc29 100644
--- a/MangaRipper.Core/MangaRipper.Core.csproj
+++ b/MangaRipper.Core/MangaRipper.Core.csproj
@@ -55,7 +55,6 @@
     <Compile Include="Framework.cs" />
     <Compile Include="IMangaService.cs" />
     <Compile Include="Downloader.cs" />
-    <Compile Include="Helper\ChapterProgress.cs" />
     <Compile Include="Extension.cs" />
     <Compile Include="MangaFoxService.cs" />
     <Compile Include="MangaHereService.cs" />
diff --git a/MangaRipper.Core/Parser.cs b/MangaRipper.Core/Parser.cs
index 5497988..ade82cc 100644
--- a/MangaRipper.Core/Parser.cs
+++ b/MangaRipper.Core/Parser.cs
@@ -8,10 +8,21 @@
 
 namespace MangaRipper.Core
 {
+    /// <summary>
+    /// Looking for manga/chapter information in html, using regex.
+    /// </summary>
     class Parser
     {
         private static Logger logger = LogManager.GetCurrentClassLogger();
 
+        /// <summary>
+        /// Looking for chapter information in html code.
+        /// </summary>
+        /// <param name="regExp">The regex with 2 captured groups.</param>
+        /// <param name="input">The html code.</param>
+        /// <param name="nameGroup">The group name that capture chapter name.</param>
+        /// <param name="valueGroup">The group name that capture chapter url.</param>
+        /// <returns></returns>
         public IList<Chapter> ParseGroup(string regExp, string input, string nameGroup, string valueGroup)
         {
             logger.Info("> ParseGroup: {0}", regExp);
@@ -30,6 +41,13 @@ public IList<Chapter> ParseGroup(string regExp, string input, string nameGroup,
             return list.Distinct().ToList();
         }
 
+        /// <summary>
+        /// Using regex to capture a group with input html code.
+        /// </summary>
+        /// <param name="regExp">The regular expression</param>
+        /// <param name="input">HTML string</param>
+        /// <param name="groupName">Name of captured group. It's returned information.</param>
+        /// <returns></returns>
         public IList<string> Parse(string regExp, string input, string groupName)
         {
             logger.Info("> Parse: {0}", regExp);