Pulitzer Prize Winner Joseph A. Livingston (right), economics editor of the Philadelphia Bulletin" and writer of the syndicated "Business Outlook" column, talks with student demonstrators on the Regent's Plaza yesterday. Livingston was here to address the 52nd annual meeting of the University Press Club of Michigan. The students were part of a group of several hundred who marched through the Literary College Building, and the Angell-Haven-Mason Hall complex during the afternoon following Thursday night's campus disorders.