Index: /qipapers.bib
===================================================================
--- /qipapers.bib	(revision 225)
+++ /qipapers.bib	(revision 226)
@@ -18634,2 +18634,10 @@
   author = {Lindner, M. and Nir, G. and Medalion, S. and Dietrich, H.R.C. and Rabin, Y. and Garini, Y.}
 }
+@article{Beleggia2004,
+  year = {2004},
+  title = {On the transport of intensity technique for phase retrieval},
+  pages = {37-49},
+  journal = {Ultramicroscopy},
+  volume = {102},
+  author = {Beleggia, M. and Schofield, M.A. and Volkov, V.V. and Zhu, Y.}
+}