Fowler, William B.; Maenchen, George; Wilson, Powell M.; Saphir,George & Wright, Robert W. Production of a Theta Degree Particle Without an AssociatedHyperon in a Pi-P Collision, report, February 29, 1956; (https://digital.library.unt.edu/ark:/67531/metadc890831/m1/1/: accessed November 12, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .