Transversely piecewise linear foliations of codimension one on closed 3-manifolds are deformed by surgery. We will show the surgery formula for the discrete Godbillon-Vey invariant of these foliations.
Norikazu HASHIGUCHI. "A surgery formula for the discrete Godbillon-Vey invariant." J. Math. Soc. Japan 56 (4) 1203 - 1209, October, 2004. https://doi.org/10.2969/jmsj/1190905455