Patents:
Sen, M.K., P.L Stoffa, and F. Liu, 2003, Angle dependent surface multiple attenuation for two-component marine bottom sensor data, US 6,654,693 B2 granted on 11/25/03.
Ziolkowski, A.M., and P.L. Stoffa, 1984, Determination of far field signatures, for instance of seismic sources, US 4,476,550.