Since Duluth, Georgia, is named in honor of our Minnesota city, I think all Duluth, Georgia, references count as indirect references to the original Duluth. Here's how Wikipedia explains the origins of a Duluth in Georgia:

Howell's Crossing was renamed "Duluth" in 1871 after Congress funded a north–south railroad line into the community. It was named after the city of Duluth, Minnesota. The Midwestern city had gotten its own railroad connection not long before, which had prompted Rep. J. Proctor Knott, a Kentucky Democrat, to make a speech in Congress mocking the project as wasteful. That speech drew national attention. According to contemporary reports, Evan P. Howell himself jokingly suggested the name change in a speech about the arrival of railroad service in the Georgia town.