Joe Shuster, of Superman fame, did a comic strip in Continental Issue One, (a digest sized publication from the 1950s, see HERE) The only published information on the magazine appears in Craig Yoe's book Secret Identity, but I believe, having browsed the magazine a bit, that it comes from the house of Lenny Burtman somehow. It has a New York origin and some of the photographs included have the early Burtman look. Undocumented as far as I can tell, but quite scarce, and with the Shuster drawings (used to introduce columns and news notes) quite unusual, especially given the story told in Yoe's book. Although Edward Mishkin figures in the story, could the source be Lenny Burtman trying out the periodical format? A bit of comic history either way.
