updated reference to medium-grain method in user's guide

docs/USERS_GUIDE.html

@@ -812,7 +812,8 @@ A. N. Yzelman and Rob H. Bisseling, SIAM Journal of Scientific Computation, Vol.
 A. N. Yzelman and Rob H. Bisseling, Parallel Computing, Vol. 37, Issue 12, pp. 806-819 (2011).<br>
 [<a id="cite3" href="">3</a>]
 <em>A medium-grain method for fast 2D bipartitioning of sparse matrices</em>,
-Dani&euml;l M. Pelt and Rob H. Bisseling, submitted for publication (2013).<br>
+Dani&euml;l M. Pelt and Rob H. Bisseling, Proceedings IEEE International Parallel
+and Distributed Processing Symposium 2014, IEEE Press, pp. 529-539. <br>
 [<a id="cite4" href="http://www.sciencedirect.com/science/article/pii/S0167819113000690">4</a>]
 <em>A new metric enabling an exact hypergraph model for the communication volume in distributed-memory parallel applications</em>
 O. Fortmeier, H. M. B&uuml;cker, B. O. Fagginger Auer, R. H. Bisseling, Parallel Computing, Vol. 39, Issue 8, pp. 319-335 (2013).<br>