diff --git a/src/common/kiwix/indexer.cpp b/src/common/kiwix/indexer.cpp
index fad04d97c..4b91b67ac 100644
--- a/src/common/kiwix/indexer.cpp
+++ b/src/common/kiwix/indexer.cpp
@@ -100,7 +100,8 @@ namespace kiwix {
 	    std::cout << "Indexing " << url << "..." << std::endl;
 	  }
 
-	  this->indexNextArticle(url, this->htmlParser.title,
+	  this->indexNextArticle(url, 
+				 this->htmlParser.title,
 				 removeAccents(this->htmlParser.title), 
 				 removeAccents(this->htmlParser.keywords),
 				 removeAccents(this->htmlParser.dump));
diff --git a/src/common/kiwix/indexer.h b/src/common/kiwix/indexer.h
index 6955aa030..27fd521bb 100644
--- a/src/common/kiwix/indexer.h
+++ b/src/common/kiwix/indexer.h
@@ -25,8 +25,11 @@ namespace kiwix {
     
   protected:
     virtual void indexNextPercentPre() = 0;
-    virtual void indexNextArticle(string &url, string &title, string &unaccentedTitle,
-				  string &keywords, string &content) = 0;
+    virtual void indexNextArticle(const string &url, 
+				  const string &title, 
+				  const string &unaccentedTitle,
+				  const string &keywords, 
+				  const string &content) = 0;
     virtual void indexNextPercentPost() = 0;
     virtual void stopIndexing() = 0;