The phrase "several studies" refers to a group or collection of multiple research projects, investigations, or inquiries that have been conducted on a particular topic. These studies may involve different methods and approaches, but they all focus on understanding some aspect of the same subject matter. The term can also be used to describe several pieces of evidence or data that support a certain conclusion or theory. In essence, "several studies" indicate there is a body of research on a particular topic, providing insight into various aspects and contributing to our overall knowledge about it.