 The  <a href = "http://www.cs.cornell.edu/Info/People/jackson/papers/tp-in-cd-abstract.html"> abstract </a> is available, as is the full text in  <a href="http://www.cs.cornell.edu/Info/People/jackson/papers/tp-in-cd-92.dvi.gz">dvi</a>(39K) and  <a href="http://www.cs.cornell.edu/Info/People/jackson/papers/tp-in-cd-92.ps.gz">postscript</a>(76K) formats. <p>
