Broadcasting Yearbook, 1942 edition, page 436:
 
1942 Broadcasting Yearbook chronology
Time, September 3, 1945, pages 64, 66:
      RADIO      
Pioneer
    Detroit's WWJ was born August 20, 1920. Broadcasting was then mostly stutter and static, and reception was mostly a matter of cat's whiskers and crystals. When the station was just eleven days old, its listeners were invited to hold "wireless parties" in their homes, to hear the first U.S. broadcast of election returns. A month later, WWJ (then called 8MK) aired radio's first vocal program, a soprano singing The Last Rose of Summer.
    Ever since then WWJ has been scoring radio firsts right & left. It claims to have broadcast the first play-by-play accounts of baseball and football games, World Series game (1920), prize fight, full symphony concert (with Ossip Gabrilowitsch and the Detroit Symphony). Walter Hampden, Fanny Brice, Fred Waring, Ty Cobb, Lillian Gish and Thomas E. Dewey (singing with an Owosso church choir) made their radio debuts over WWJ.
    Last week WWJ celebrated its 25th anniversary, and reasserted its claim to being the world's first commercial radio station. That claim used to be pooh-poohed by Pittsburgh's powerful KDKA. This year the National Association of Broadcasters finally decided the question in WWJ's favor; KDKA, it said, was ten and a half weeks younger.
    The station, founded by Detroit News Publisher William E. Scripps, this year chalked up still another first: it was the first big network station to ban all electrical transcriptions.
NAB Reports, September 14, 1945, Volume 13, No. 37, page 401:
RYAN  WRITES  TIME  MAGAZINE

    NAB President J. Harold Ryan has sent the following letter to Mr. Henry R. Luce, Editor of Time Magazine:

    In the September third issue of Time under the Radio Section on page 66 occurs the following statement:
"Last week WWJ celebrated its 25th anniversary, and reasserted its claim to being the world's first commercial radio station. That claim used to be pooh-poohed by Pittsburgh's powerful KDKA. This year the National Association of Broadcasters finally decided the question in WWJ's favor; KDKA, it said, was ten and a half weeks younger."
    While it is true that this year the National Association of Broadcasters published a Chronology of Radio, your correspondent apparently has drawn from it an entirely erroneous conclusion. The Chronology is a reprint from Broadcasting's Year Book of 1942. Since this publication is not available to those organizations who were planning salutes to Radio on the Twenty-Fifth Anniversary of the year when commercial broadcasting began we reprinted the Chronology, solely for their guidance. To imply that the mere reprint of a chronology amounts to a "final decision" on a disputed date of history is manifestly unfair to the stations involved and to the NAB. It was not the intention, nor is it the prerogative of the NAB to attempt to decide the relative claims of two pioneer broadcasting stations. The statement, therefore, that this Association decided the question in WWJ's favor is in error and does an injustice to KDKA. We would appreciate your making the necessary correction.
Journal of the Association for Education by Radio, October, 1945, page 23:

WWJ first--KDKA has long claimed the title of pioneer commercial radio station in the United States. It can make that claim no longer. The NAB has decided that the first commercial radio station was Detroit's WWJ which, call letters 8MK, was born August 20, 1920. No reference was made in NAB's decision to the claims of WHA, the pioneer educational station which, it is alleged, was on the air several years earlier.

December, 1945, page 64:

NAB's Willard D. Egolf has written that the NAB was not settling officially the dispute between WWJ and KDKA, to which editorial reference was made in the October Journal. The Chronology of Radio which was reprinted by NAB, and which listed the earlier date for WWJ, was only for the guidance of stations and did not constitute an official decision.
Broadcasting, October 15, 1945, page 91:

Westinghouse  and  NAB  Plan  Meeting  To  Discuss  Resignation  of  Six  Outlets
DIFFERENCES between Westinghouse Radio Stations Inc. and NAB, which led to resignation last week of the six Westinghouse outlets from the association, will be discussed at a meeting of the two groups to be held sometime this week.
    Westinghouse action was the culmination of years of dissatisfaction with NAB operations, the company indicated. Owning six stations--WBZ Boston, WBZA Springfield, KYW Philadelphia, KDKA Pittsburgh, WOWO Fort Wayne, KEX Portland--Westinghouse felt it had not been receiving from NAB the recognition an operation of this size deserved.
    Westinghouse was further aggravated last spring by an NAB broadcast chronology in which the 1920 first-commercial-station controversy was not handled to its satisfaction. Then in the Sept. 3 issue of Time magazine appeared an article on the same controversy which further annoyed Westinghouse.
    The company felt NAB's handling of Radio's 25th Anniversary was not fair, and NAB's handling of the Time article was displeasing to it.
    Ex-president of NAB, J. Harold Ryan, wrote a letter correcting allegedly inaccurate statements in the magazine article, but this letter was not acknowledged nor was it published.
    Westinghouse has two NAB committee chairmanships--Leslie W. Joy, KYW, chairman of Public Relations Executive Committee; John B. Conley, KEX, chairman of Committee on Office Forms & Practices.
    No formal statement was issued by either NAB or Westinghouse pending the meeting this week at which proposals for settlement of diffferemces will be discussed.
The Billboard, October 27, 1945, page 5:
 
Westinghouse  Exits  From  NAB
With  All  Five  of  Its  Stations

    NEW  YORK, Oct. 22--Westinghouse has pulled its stations out of NAB. Reasons behind the move are twofold, depending on who's doing the talking. Westinghouse execs infer the resignation stems from fact that their organization, which numbers some of the oldest stations in the country, got a once over lightly from the NAB bally for 25th anniversary of the biz.
    NAB execs say Westinghouse has been unhappy for some time over what it describes as "limitations of its role in NAB." Sans the sugar this means, NAB feels Westinghouse has wanted a bigger say in NAB control while the trade association feels that Westinghouse already has a fair say.
    Westinghouse outlets are KDKA, Pittsburgh; KYW, Philadelphia: WOWO, Fort Wayne; WBZ-WBZA, Boston-Springfield, Mass., and KEX, Portland, Ore.
Commercial Broadcasting Pioneer: The WEAF Experiment by William Peck Banning, 1946, page 50 [footnote]:

7 Editor's note: With regard to the question of broadcasting pioneering, the National Association of Broadcasters in 1945 decided the question in favor of WWJ, saying that KDKA was ten and a half weeks younger.
NAB Reports, April 14, 1947, Volume 15, No. 14, pages 292-293:

A Statement by Dr. Kenneth H. Baker, NAB Director of Research

    It has come to our attention recently in two rather serious instances that the NAB is supposed to have "settled" the long-standing controversy between KDKA and WWJ concerning their conflicting claims to recognition as the radio station inaugurating the American system of broadcasting. Apparently the basis upon which this presumption is founded is the publication in May, 1945, of a "Chronology" which was part of the literature used during the promotion of radio's 25th anniversary. This chronology was not based on any original research by NAB. It was simply a reprint of material appearing in other publications. At the time of its publication, the NAB had neither the staff nor the facilities to prepare such material independently. The reproduction of this chronology carried with it no certification as to its accuracy nor any agreement or disagreement with its content.
    The NAB did not in May, 1945, and could not now properly take any final position in this internecine dispute.
    The only official records available have been carefully scanned by NAB's Research Department. These are summarized as follows:
 
KDKA

1916
1 August 1, 1916, 8XK licensed as "new special land station" to Frank Conrad, Pittsburgh.

1917-1919
WORLD WAR I
(All amateurs off the air)

1920
1 May 1, 1920, 8XK licensed as "new special land station" to Frank Conrad, Pittsburgh.

1920
1 November 1, 1920, KDKA listed as "new commercial land station" owned by Westinghouse Company.
   
WWJ

Date Unknown
8MK, said to be ancestor of WWJ, not included in Bureau of Navigation Lists.

1921
1 June 30, 1921, 8CS first listed as licensed to W. J. Scripps, Detroit.

1921
1 November 1, 1921, WBL, listed as "new commercial land station", Detroit, owned by Detroit News.

1922
1 April 1, 1922, Announcement of change of call letters from WBL to WWJ.

1 Entries from "Radio Service Bulletin, Bureau of Navigation, Department of Commerce" for the dates indicated. This was a monthly service publication and constituted the only public record of changes in station operation.
2 From the "Amateur Radio Stations of the United States, Bureau of Navigation, Department of Commerce." This was an annual listing of stations licensed and operating. It was published as of June 30 of each year and sometimes the additions for June were included in this list rather than the Service Bulletin, of the following July 1st. 8CS could therefore have been licensed in June, 1920.
KENNETH H. BAKER,      
Director of Research.      
Broadcasting, April 14, 1947, page 93:

First  Station  Feud  Reopened  by  NAB
U.S.  Records  Covering  KDKA  And  WWJ  Are  Summarized

NAB last week reopened the controversy between KDKA Pittsburgh and WWJ Detroit over which station was the pioneer broadcaster. Dr. Kenneth H. Baker, NAB Director of Research, summarized official Government records on the subject after extensive research at the FCC, Dept. of Commerce and other agencies.
    Occasion for publication of a summary of official records was appearance in the book The WEAF Experiment of a footnote attributing to NAB facts appearing in promotion material used in 1945 for the 25th anniversary of broadcasting. NAB disclaimed any part in preparation of the factual material, saying it had appeared in other publications.
    NAB explained that it "did not in May 1945 and could not now properly take any final position in its internecine dispute."
Broadcasting, December 7, 1953, page 5:
closed  circuit
*     *     *
WESTINGHOUSE Radio Stations Inc., out of NARTB fold for some eight years, expected to rejoin after Jan. 1 when Chris Witting assumes WRS presidency. Stations will mean $12- 14,000 additional revenue for NARTB.

[Note: From 1951 to 1958 the National Association of Broadcasters (NAB) changed its name to the National Association of Radio and Televison Broadcasters (NARTB).]