sentences:  Rivers and Zinn were among a group of faculty members who in 1979 defended the right of the school's clerical workers to strike and were threatened with dismissal after refusing to cross a picket line.Zinn came to believe that the point of view expressed in traditional history books was often limited.Biographer Martin Duberman noted that when he was asked directly if he was a Marxist, Zinn replied, "Yes, I'm something of a Marxist."