References
- Culler , M. 1981 . Using surfaces to solve equations in free groups . Topology , 20 ( No 2 ) : 133 – 145 .
- Comerford , Leo P. Jr. and Edmunds , Charles C. Products of commutators and products of squares in a free group , to appear
- Ol’shanskii , A. 1989 . Homomorphism diagrams of surface groups . Siberian Math. J. , 30 : 961 – 979 .
- Wicks , M. J. 1962 . Commutators in free products . J. London Math. Soc. , 37 : 433 – 444 .
- Commerford , L. P. Jr. , Commerford , J. A. and Edmunds , C. C. 1991 . Powers as products of commutators . Com. in Alg. , 19 ( 2 ) : 675 – 684 .
- Vdovina , A. 1994 . Products of squares in a free group, Vestnik MSU . Math. Mech. , : 26 – 30 .
- Vdovina , A. On the number of nonorientable Wicks forms in a free groups . Proc. Edinburgh Royal Soc. , to appear
- Massey , W. 1977 . Algebraic Topology: An Introduction , Springer-Verlag .
- Zeischang , H. , Vogt , E. and Coldewey , A.-D. Flächen und ebene discontinuiearliche Gruppen , Berlin-Heidelberg-New York, Springer, 1970 .
- Robinson , R. W. and Wormald , N. C. 1984 . “ Existence of long cycles in random cubic graphs ” . In Enumeration and Design , Edited by: Jackson , D.M. and Vanstone , S.A. 251 – 270 . Toronto : Academic Press .
- Mc Kay , B. D. and Wormald , N. C. 1984 . Automorphisms of random graphs with specified vertices . Combinatorica , 4 ( No 4 )
- Read , C. 1970 . Some unusual enumeration problems . Ann. N. Y. Acad. Sci. , 175 : 314 – 326 .