I am surprised a gin based drink is being listed as "southern" (although it has some similarity to the Ramos Fizz created in New Orleans.) Difford’s has essentially the same recipe listed as the “Celery Sour” with some differences in proportions. (Per Difford the original "celery sour" comes from a 1917 non-alcoholic cocktail in a book by a St. Louis bartender, so the gin is a later addition or the alcohol component was inadvertently omitted in the publication...I suspect the latter. It didn't include egg white.) I am inclined to listing this as an “altered recipe” of the “Celery Sour” with The Grey in Savannah as the place where it was created per the contributor, although it doesn’t show up on their current online cocktail menu. I did locate an old link to their menu showing a “Celery Sour” https://www.opentable.com/r/the-grey. There the egg white is not mentioned but it is under Vintage cocktails as "Gin, Lemon, Pineapple, Celery Bitters"