Matthew C. Wheeler and Harry H. Hendon (2004). An All-Season Real-Time Multivariate MJO Index: Development of an Index for Monitoring and Prediction. Monthly Weather Review, 132, 1917-1932.
Alexis Donald, Holger Meinke, Brendan Power, Aline de H. N. Maia, Matthew C. Wheeler, Neil White, Roger C. Stone and Joachim Ribbe. (2006), Near-Global Impact Of The Madden-Julian Oscillation On Rainfall. Geophysical Research Letters Vol. 33, No. 9.
Donald, A.M. (2005), The application of the real-time multivariate Madden-Julian Oscillation index to intraseasonal rainfall forecasting in the mid-latitudes. MSc Dissertation, University of Southern Queensland, Toowoomba, Australia. Available here.