Stencel R.E., J.L. Linsky, A. Brown, C. Jordan, K.G. Carpenter, R.F. Wing, and S.J. Czyzak, Monthly Notices Of The Royal Astronomical Society 196, 47P-53P (1981).
Stencel R.E., C. Jordan, R.F. Wing, J.L. Linsky, K.G. Carpenter, A. Brown, and S.J. Czyzak, Bulletin Of The American Astronomical Society 12, (1980).
and 
