Citizens Oil Co. was formed in 1936 and was a franchise of Moore’s Greyhound brand. The greyhound was later incorporated into the Citizens logo and in 1951 they merged with Speed Oil Company of Atlanta. Dealer stations used that Citizens 77 branding. [The sign was lost during Hurricane Michael in 2018].
Vanishing Georgia: Photographs by Brian Brown 
Sadly, this sign became a victim of hurricane Michael in 2018.
Hate to hear that, Mark. It was one of my “landmarks” when reaching Calvary after a day of long driving.