Country Music Sources. Guthrie T. Meade, Jr.; Dick Spottswood; Douglas S. Meade. Chapel Hill: University of North Carolina Press, 2002.

"When Gus Meade died suddenly on February 9, 1991, he was only 58 years old and still in the midst of preparing this monumental work." - Dick Spottswood

It would be over 10 years before Gus' "biblio-discography" would be published, and the editors had quite a time making sense of some of what they had. Gus used short abbreviations for all kinds of works. The editors identified most of those, but not all.

For what it's worth, here are the significant parts of the headnotes to In the Bright Mohawk Valley:

****
'A Lady in Love,' ca. 1889/James J. Kerrigan, 1896; Ref: (1) WCS#24(Oct. 1889), p. 17, 'A Lady In Love'; Delaney #13
****

"WCS" is Wehman's Collection Of Songs (NYC: Henry J. Wehman, 1884-94), 42 issues.

"Delaney" is Delaney's Song Book, #1-88 (NYC: Wm W. Delaney, 1892-1921).

I suppose that someone will have to go to the Library of Congress, or some such place, to track down the Wehman/Delaney references.