--- ray/doc/ray.1	2011/06/22 00:13:25	1.21
+++ ray/doc/ray.1	2011/07/15 17:45:46	1.22
@@ -1552,6 +1552,12 @@ in Lausanne, Switzerland.
 .NH 1
 References
 .LP
+Ward, G., R. Mistrick, E.S. Lee, A. McNeil, J. Jonsson,
+``Simulating the Daylight Performance of Complex Fenestration Systems
+Using Bidirectional Scattering Distribution Functions within Radiance''
+.I "Journal of the Illuminating Engineering Soc. of North America",
+April 2011.
+.LP
 Cater, K., A. Chalmers, G. Ward,
 ``Detail to Attention: Exploiting Visual Tasks for Selective Rendering,''
 .I "Eurograhics Symposium on Rendering",