"Duets : complete edition in 5 vols. Vol. 4: soprano, tenor & piano" . . . . . . . . "Duets : complete edition in 5 vols. Vol. 3: 7 duets for 2 female voices a cappella" . . "Duets : complete edition in 5 vols. Vol. 1: 7 duets for 2 female voices & piano" . "Duets : complete edition in 5 vols. Vol. 2: 6 duets for 2 female voices & piano" . . "Duets : complete edition in 5 vols. Vol. 5: soprano, tenor (baritone) & piano" . . . .