Spedding, G R, Klinke, J and Long, S R (1996). Estimating $\omega(k)$ in an unsteady, wind-generated surface wave field from the 2D complex wavelet transform of the surface slope. Proc.\ The Air-Sea Interface, Radio and Acoustic Sensing, Turbulence and Wave Dynamics, Marseille, 24--30. June 1993. RSMAS, University of Miami. 373--382