CQ came from European telegraphy procedure, the Telegraphy Union oversaw this, they later became the International Telecommunications Union and when the United Nations was formed became a committee within it.

German Telegraph Historian, Gregor Ulsamer, DL1BFE supplied this unattributed information.  None of my fellow Morse Telegraph Club and Radio Officer contacts know the citation, but we've been around for a long time. 

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DR