@article{cj99-03,
       author={Stephen Fenner and Frederic Green and Steven Homer and Alan 
               L. Selman and Thomas Thierauf and Heribert Vollmer},
       title={Complements of Multivalued Functions},
       journal={Chicago Journal of Theoretical Computer Science},
       volume={1999},
       number={3},
       publisher={MIT Press},
       month={March},
       year={1999}
}