diff --git a/src/HTMLRenderer/HTMLRenderer.h b/src/HTMLRenderer/HTMLRenderer.h
index 9b61c32..fd8ef07 100644
--- a/src/HTMLRenderer/HTMLRenderer.h
+++ b/src/HTMLRenderer/HTMLRenderer.h
@@ -379,6 +379,7 @@ class HTMLRenderer : public OutputDev
         double draw_tx, draw_ty; 
 
         // some metrics have to be determined after all elements in the lines have been seen
+        // see TextLineBuffer.h
         class TextLineBuffer;
         friend class TextLineBuffer;
         TextLineBuffer * text_line_buf;
diff --git a/src/HTMLRenderer/TextLineBuffer.h b/src/HTMLRenderer/TextLineBuffer.h
index e13ef20..07c347d 100644
--- a/src/HTMLRenderer/TextLineBuffer.h
+++ b/src/HTMLRenderer/TextLineBuffer.h
@@ -6,6 +6,13 @@
 
 namespace pdf2htmlEX {
 
+/*
+ * Store a series of 
+ *  - Text
+ *  - Shift
+ *  - State change
+ * within a line
+ */
 class HTMLRenderer;
 class HTMLRenderer::TextLineBuffer
 {