Historical clue formulations

• All that a greedy businessperson thinks about? — 2021-07-06
• Cash bars? [Abba] — 2021-02-21
• 1976 Abba hit — 2012-01-16
• 1976 Abba song ... or a hint to the starts of 17-, 23-, 38- and 50-Across — 2011-11-29