Barbershop music encompass both men's and women's singing in the barbershop style – in quartets and choruses. Sweet Adelines International and Harmony, Inc. are two women's barbershop singing organizations that operate globally and in North America, respectively. Other women's organizations include the Ladies Association of Barbershop Singers (LABBS) in the United Kingdom, the Spanish Association of Barbershop Singers (SABS) in Spain, and the Irish Association of Barbershop Singers (IABS) in Ireland. A barbershop quartet is an ensemble of four people who sing a cappella in the exacting barbershop music genre. In North America most male barbershop quartet singers belong to the Barbershop
Homer's Barbershop Quartet and his sister Lisa notice a picture of their father, Homer, on the cover of an old LP album. Homer explains to his family that he, Principal Skinner, Barney Gumble, and Apu Nahasapeemapetilon recorded a barbershop quartet album in 1985, which catapulted them to national fame. He narrates to his family the story of how the band formed, reached the pinnacle of success, and eventually folded. At the end of the episode, the group reunites to perform a concert on the roof of Moe's Tavern, singing their number-one hit "Baby on Board". Throughout the episode, several references are made to