How can I list all foreign keys referencing a given table in oracle database?

That will be difficult. The Windchill database doesn't use foreign key constraints, so there's no easy way to get a list of which table references which other tables.

Though, you may be able to use the classnamekey columns to get this information. For each foreign key column in a table, there is a corresponding classnamekey column that holds the name of the table that the foreign key references. For example, the ida3masterreference column of WTPart is a foreign key to the WTPartMaster table. There is a corresponding column in WTPart named classnamekeymasterreference which contains the text 'wt.part.WTPartMaster'. As another example, the ida3containerreference column of WTPart contains a foreign key to the container context of the part (which could be a product, project, library, etc). The corresponding classnamekeycontainerreferen column will contain text like 'wt.pdmlink.PDMLinkProduct', 'wt.projmgmt.admin.Project2', or 'wt.inf.library.WTLibrary', depending on the type of container.

What you could do is get a list of all the columns beginning with classnamekey for each table. Then, for each of these columns, get a list of the distinct values in that column. From that, you can figure out how the tables are connected.