please provide the refernces and citation for the following sentences.                                      Gothenburg is Sweden's second-largest city, with a population of approximately 580,000 people. The city is located on the west coast of Sweden, on the Göta älv river. Gothenburg is a major port city and a center for industry, commerce, and culture. Gothenburg is a popular tourist destination, attracting visitors from all over the world. The city is known for its maritime heritage, its vibrant cultural scene, and its beautiful natural surroundings. Some of the most popular tourist attractions in Gothenburg include: Liseberg Amusement Park, Universeum Science Center, Gothenburg Museum of Art, Gothenburg Botanical Garden...