diff --git a/src/lab/point/references.html b/src/lab/point/references.html
index 9bcf7950..33495407 100644
--- a/src/lab/point/references.html
+++ b/src/lab/point/references.html
@@ -16,7 +16,7 @@
       <p>
 	Pixel brightness transformation
 	<u>
-	  <a href="http://www.icaen.uiowa.edu/%7Edip/LECTURE/PreProcessing1.html#greyscale" target ="_blank">
+	  <a href="http://user.engineering.uiowa.edu/~dip/lecture/PreProcessing1.html" target ="_blank">
 	    http://www.icaen.uiowa.e.../PreProcessing1.html
 	  </a>
 	</u>
@@ -38,7 +38,7 @@
 	Gray scale transformations
 	<u>
 	  <a
-	     href="http://www.google.co.in/url?sa=t&amp;source=web&amp;cd=27&amp;ved=0CDgQFjAGOBQ&amp;url=http%3A%2F%2Fwww.eng.iastate.edu%2Fee528%2Fsonkamaterial%2Fchapter_4.htm&amp;ei=cUKkTLOuLIqWcfmDyM0I&amp;usg=AFQjCNHuwummnhYRfH3drcW2-GpMAH3xnQ&amp;sig2=9sqPsUrEzwX2A_kW2O5dbA" target="_blank">
+	     href="http://www.icaen.uiowa.edu/%7Edip/LECTURE/PreProcessing1.html#greyscale" target="_blank">
 	    http://www.google.co.in/url?sa=t&amp...5dbA
 	  </a>
 	</u>