by Edna Yost, in collaboration with Dr. Lillian M. Gilbreth. Robert P. Thomas in collaboration with William V. Weber. By J. Markowitz in collaboration with J. Archibald and H. G. Downie. by L. M. Parr in collaboration with C. A. Hendley. [by] Albert V. Hahn, in collaboration with Roger Williams and Herman Zabel. J. P. Holman in collaboration with W. J. Gajda, Jr. A. G. Brown, in collaboration with D. W. Langridge & J. Mills. In statistical collaboration with Jaakko Kihlberg. J. Tinsley Oden ; in collaboration with Graham F. Carey. K. D. Stroyan in collaboration with W. A. J. Luxemburg.