Cleveland Plain Dealer, May 22, 1919, page 19:

ALTER  WIRELESS  CONCERT
________

Programs  to  be  Announced  in  Advance  for  Thursday  Stunt.
________

    The wireless concerts, sent out each Thursday evening between 8 and 10 o'clock from the plant of the Glenn L. Martin Co., will not be given this evening, pending a decision on a request to change the wave length. The concert will be resumed next Thursday evening.
    Beginning next week, the complete program will be announced in advance and printed on this page each Thursday morning.