[CR1] T.E. Cecil and P.J. Ryan, On the number of top-cycles
of a tight surface in 3-space, J. London Math. Soc.
30 (1984) 335-341.
The authors give a nice description of the results to date and of top
sets and cycles. They give sharp bounds on the number of top cycles
depending only on the Euler characteristic of the surface; explicit
examples are given for each surface.
10/12/94 dpvc@geom.umn.edu --
The Geometry Center