WorldCat lets you search the collections of libraries in your community and thousands more around the world.
Google Scholar searches specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research.
You can narrow search results to the fields JSTOR uses for categorization of metadata. Each field is represented in a search by its abbreviation. The example above (au:smith) will find all items for which Smith is listed as an author. Appending ty:fla to a search ("Greek slave" ty:fla) will limit a search to full-length articles, and ty:brv will limit a search to book reviews.
Other frequently used field abbreviations are:
Consider the different relationships your object may have accrued in antiquity (who made, used, and viewed it? How did they interact with it? In what circumstances?). What might the object have represented to these people? How might their perspective change its meaning, specifically in terms of how slavery and enslaved people are shown?