1. Public Health Bull;Neal,1937
2. Neal P. A., Edwards, T. I., Reinhart, W. H., Hough, J. W., DallaValle, J. M., Goldman, F. H., Armstrong, D. W., Gray, A. S., Coleman, A. L., Postman, B. F. Public Health Bull. No. 263. Washington, Gov. Print. Off., 1941.