an Entity references as follows:
The men's 1960 United States Olympic trials for track and field for men were held at the Stanford Stadium at Stanford University in California, between July 1 and 2. The 20 kilometer walk trials were held in Baltimore, Maryland, on July 17, and the 50 kilometer walk trials were held on July 3 in Pittsburgh, Pennsylvania. Two marathon trials were held between two races, the AAU National Championships in Yonkers, New York, on May 22 and the Boston Marathon in Boston, Massachusetts, on April 19. As it turned out, the three selectees were the top 3 at Yonkers, but that is because Gordon McKenzie was also the first American finisher at Boston.