diff --git a/src/main/java/org/apache/commons/csv/CSVFormat.java b/src/main/java/org/apache/commons/csv/CSVFormat.java
index b9fc0e67..9347957b 100644
--- a/src/main/java/org/apache/commons/csv/CSVFormat.java
+++ b/src/main/java/org/apache/commons/csv/CSVFormat.java
@@ -588,7 +588,8 @@ public class CSVFormat implements Serializable {
      *            <tt>true</tt> when the parser should skip empty lines
      * @param recordSeparator
      *            the line separator to use for output
-     * @param nullToString TODO
+     * @param nullToString 
+     *            the String to use to write <code>null</code> values.
      * @param header
      *            the header
      * @throws IllegalArgumentException if the delimiter is a line break character