--- manual/manual_references.bib	2016/03/29 14:51:17	1.54
+++ manual/manual_references.bib	2016/09/16 18:52:25	1.55
@@ -268,6 +268,18 @@
  pages          = {1891--1910},
                   }
 
+@Article{for-eta:15,
+ author         = {Forget, G. and Campin, J.-M. and Heimbach, P. and Hill, C. N. and Ponte, R. M and Wunsch, C.},
+ title          = {{ECCO} version 4: an integrated framework for non-linear inverse modeling and global ocean state estimation},
+ journal        = {Geoscientific Model Development},
+ volume         = {8},
+ year           = {2015},
+ number         = {10},
+ pages          = {3071--3104},
+ url            = {http://www.geosci-model-dev.net/8/3071/2015/},
+ doi            = {10.5194/gmd-8-3071-2015}
+}
+
 @Article{gas-eta:90,
  author		= {P. Gaspar and Y. Gr\'egoris and J.-M. Lefevre},
  year		= 1990,