diff --git a/README.md b/README.md
index b1ae6e2..f8b6fd4 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,9 @@ gocronexpression
 
 Go language (golang) cron expression parser. Given a cron expression and a time stamp, you can get the next time stamp which satisfy the cron expression.
 
+The reference documentation for this implementation is found at
+https://en.wikipedia.org/wiki/Cron#CRON_expression
+
 Install
 -------
 
@@ -18,7 +21,14 @@ Import the library:
 
 Simplest way:
 
-    ...
-    nextTime := cronexpression.NextTimeFromCronString("* * 29 2 *", time.Now())
+    nextTime := cronexpression.NextTimeFromCronString("0 0 29 2 *", time.Now())
+
+Assuming `time.Now()` is "2013-08-29 09:28:00", then `nextTime` will be "2016-02-29 00:00:00".
+
+If you need to reuse many times a cron expression in your code, it is more efficient
+to create a `CronExpression` object once and keep a copy of it for reuse:
+
+    cronexpr := cronexpression.NewCronExpression("0 0 29 2 *")
+    nextTime := cronexpr.NextTime(time.Now())
+    
 
-Assuming *time.Now()* is "2013-08-29 09:28:00", then *nextTime* will be "Monday, February 29, 2016 00:00:00".