With the mention of Child earlier in the threas I was doing a little digging and came across the following:
ESSAYS IN THE STUDY OF FOLK-SONGS.
BY THE
COUNTESS EVELYN MARTINENGO-CESARESCO.

https://www.gutenberg.org/files/36222/36222-h/36222-h.htm
and
Phillips Barry and Anglo-American Folksong Scholarship

https://www.gutenberg.org/files/36222/36222-h/36222-h.htm
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