1. Ramified covering CP2 → S4, hyperbolicity and projective topology;Arnol'd;Siberian Math. J.,1988
2. R. Cori, Private communication, 1990.
3. Estimates of number of fixed points of area preserving transformations, VINITI;Eliashberg;Syktyvkar,1979
4. Combinatorial Enumeration;Goulden,1983
5. Folding a strip of stamps;Koehler;J. Combin. Theory,1968