Per John Bolig's Victor Black Label Discography 18000/19000 Series, the members of the American Quartet were tenors Albert Campbell and Billy Murray, and basses William F. Hooley and John H. Meyer. The Shannon Quartet side is only one mx removed from the American Quartet. Bolig indicates that Charles Hart and Harvey Hindermeyer were in the studio, but that the members of the Shannon Four (he calls it the Shannon Quartet, but I go with the label) are not listed.