If you're talking about only the women, they're Fältskog and Lyngstad. But if you add the males, they're Ulvaeus and Andersson.
fogelberg
The Visitors.
See link below for ABBA discography.
American folk singers, the Beatles and Elvis Presley.
Anni-Frid Lyngstad, Agnetha Faltskog, Benny Andersson, and Bjorn Ulvaeus.
abba
Anni-Frid Lyngstad Björn Ulvaeus Benny Andersson Agnetha Fältskog If you read the first letter in each name it reads ABBA:)
Presumably when they were born. If you mean the band itself, they adopted the name (acronym) ABBA in the summer of 1972, two years after they started performing together. (Before that they just used their first names, Bjorn & Benny, Agnetha & Frida).
fogelberg
Usher Uncle Cracker
fontella bass ed ames
The Visitors.
See link below for ABBA discography.
a-ha abba Gregory abbott ac/dc
American folk singers, the Beatles and Elvis Presley.
Mary J. Blige Toni Braxton
They were a group of singers that consitered of 4 members. They began in 1970 and split up in 1983.