Lemon sour
Lemon sour is a type of soda made by various vendors, often used in many mixed drinks. There are also alcoholic variants sold in Japan.
The Schweppes brand of lemon sour is sold by Coca-Cola. Canada Dry's lemon sour was sold by Dr Pepper/Seven Up.
Lemon sour is also a popular soda in Japan, where is it sold as an alcopop by Suntory and Coca Cola.