PRACTICAL DIO TELEGRAPHY /
ARTHUR R. NILSON
Lieutenant (Technicist) (Communications) U. S. N. R.; Member Institute of Radio Engineers; Member Radio Club of America '
J. L. HORNUNG
Fellow Radio Club of America; Associate Member Institute of Radio Engineers; Radio Instructor
McGRAW-HILL BOOK COMPANY, Inc. NEW YORK: 370 SEVENTH AVENUE
london: 6 & 8 bouverie st., e. c. 4 1928