Original sentence: The 1974 contest is notable for the participation of a number of artists who were already internationally-known names (Olivia Newton-John, Gigliola Cinquetti, Mouth and MacNeal), also as the contest which served to launch the winning group, ABBA, into global superstardom
Edited sentence: The 1974 contest is notable for the participation of a number of artists who were already internationally-known names (Olivia Newton-John, Gigliola Cinquetti, Mouth & MacNeal), also as the contest which served to launch the winning group, ABBA, into global superstardom