"Downflows Under Sunspots Detected by Helioseismic Tomography",
T. L. Duvall Jr., S. D'Silva, S. M. Jefferies, J. W. Harvey & J. Schou,
Nature, in press, 1995.
The data from the figures in this paper can be retrieved also.
A continuum movie and associated times for the '96 dynamics period is
available for downloading.
Some analyses of mdi noise sources