Jan van Oldenborgh, Geert, Magdalena A. Balmaseda, Laura Ferranti, Timothy N.Stockdale  and  David L. T. Anderson, 2005: Did the ECMWF Seasonal Forecast Model Outperform Statistical ENSO Forecast Models over the Last 15 Years? J. Climate, 18, 3240-3249.

Jan van Oldenborgh, Geert, Magdalena A. Balmaseda, Laura Ferranti, Timothy N.Stockdale  and  David L. T. Anderson, 2005: Evaluation of Atmospheric Fields from the ECMWF Seasonal Forecasts over a 15-Year Period. J. Climate, 18, 3250-3269