One of the best ways to begin a research project is to browse through the library shelves. To search the catalog by Library of Congress Subject Headings try:
Nineteen sixty-eight, A.D
Social movements--Europe--History--20th century
Vietnam War, 1961-1975--Diplomatic history
Vietnam War, 1961-1975--Peace--Congresses.
United States -- History -- 1961-1969.
United States -- Social conditions -- 1960-1980.