Publication of the Mathematics Research Center, the University of Wisconsin--Madison ; Publication of the Mathematics Research Center, the University of Wisconsin--Madison, Publication ... of the Mathematics Research Center, the University of Wisconsin--Madison ; Publication of the Mathematics Research Center, University of Wisconsin--Madison ; Publication of the Mathematics Research Center, the University of Wisconsin--Madison ; no. 45 Publication no. 46 of the Mathematics Research Center, the University of Wisconsin--Madison Publication no. 53 of the Mathematics Research Center, the University of Wisconsin--Madison Publication no. 48 of the Mathematics Research Center, The University of Wisconsin-Madison Publication of the Mathematics Research Center, University of Wisconsin--Madison ; no. 32 Publication of the Mathematics Research Center, University of Wisconsin--Madison ; no. 43