--- ray/doc/ray.1	2015/12/01 16:58:16	1.28
+++ ray/doc/ray.1	2016/05/25 18:52:45	1.29
@@ -1,4 +1,4 @@
-.\" RCSid "$Id: ray.1,v 1.28 2015/12/01 16:58:16 greg Exp $"
+.\" RCSid "$Id: ray.1,v 1.29 2016/05/25 18:52:45 greg Exp $"
 .\" Print using the -ms macro package
 .DA 09/18/2015
 .LP
@@ -1552,6 +1552,11 @@ the Ecole Polytechnique Federale de Lausanne (EPFL Uni
 in Lausanne, Switzerland.
 .NH 1
 References
+.LP
+Ward, G., M. Kurt & N. Bonneel,
+``Reducing Anisotropic BSDF Measurement to Common Practice,''
+.I Workshop on Material Appearance Modeling,
+2014.
 .LP
 McNeil, A., C.J. Jonsson, D. Appelfeld, G. Ward, E.S. Lee,
 ``A validation of a ray-tracing tool used to generate