I am writing a paper and couldn't find sources on just slurping the soups. Could anyone help.
No, that would be kind of weird. For ramen, soba, etc, you don't really slurp the soup, you slurp the noodles after picking them up with chopsticks. For noodleless soups like miso, there's nothing slurpable to pick up with chopsticks, and it makes no more sense to slurp it than it does to slurp a glass of water or a cup of tea.