Every time I've read "first Fourier transform", I've assumed it to be a misspelling of the fast Fourier transform. Recently though, I saw the term in both the title and keywords of an article from a seemingly serious, albeit not peer-reviewed, journal, Japanese Circulation Journal.
Development of a new analytical method for the electrocardiogram using short-time first Fourier transforms doesn't cite any resource or explain the algorithm. (fulltext PDF)
Is there a "first" Fourier transform?