Have you looked into the earlier works that laid the groundwork or introduced key theories? What about the more recent studies—are they building on those foundations, challenging them, or introducing fresh perspectives? Examining your topic's scholarly timeline can be beneficial in helping you thoroughly exhaust the literature.
You can map your topic's scholarly timeline on your own by keeping track of its trail from the first foundational studies through the research being conducted on the topic today. As you come across relevant information on your topic, make note of it.
An Excel spreadsheet can be a great place to record source publication information in chronological order so that the timeline can be easily constructed and clearly seen.
Research Rabbit also includes useful tool for mapping the timeline of scholarly conversation surrounding a research study:
