Sacred Music, the quarterly journal of the Church Music Association of America, has an online archive. 135 issues, dating back to 1975, are available for free download in PDF form.Anything dealing with the Orthodox Church?
Understandably, I haven't gone through the lot yet, but with Orthodoxy being increasingly high profile, I wouldn't be surprised if the more recent issues included relevant articles. Perhaps those with icons on the cover.
But Orthodox music has not been studied in universities in North America at the graduate level., Plus, a scholar would have to know all the languages to read secondary sources or at least German. Johann von Gardner's work on Russian Church music has been translated into English but one would have to be able to read german and Russian to follow upo his sources.