--- ray/doc/ray.1	2017/04/08 00:09:35	1.31
+++ ray/doc/ray.1	2017/12/24 22:01:00	1.33
@@ -1,8 +1,8 @@
-.\" RCSid "$Id: ray.1,v 1.31 2017/04/08 00:09:35 greg Exp $"
+.\" RCSid "$Id: ray.1,v 1.33 2017/12/24 22:01:00 greg Exp $"
 .\" Print using the -ms macro package
 .DA 07/10/2016
 .LP
-.tl """Copyright \(co 2016 Regents, University of California
+.tl """Copyright \(co 2017 Regents, University of California
 .sp 2
 .TL
 The
@@ -1569,6 +1569,12 @@ the Ecole Polytechnique Federale de Lausanne (EPFL Uni
 in Lausanne, Switzerland.
 .NH 1
 References
+.LP
+Lee, Eleanor S., David Geisler-Moroder, Gregory Ward,
+``Modeling the direct sun component in buildings using matrix
+algebraic approaches: Methods and validation,''
+.I Solar Energy,
+vol. 160, 15 January 2018, pp 380-395.
 .LP
 Ward, G., M. Kurt & N. Bonneel,
 ``Reducing Anisotropic BSDF Measurement to Common Practice,''