Reference between two schemas in oracle

Suppose you have two different schemas in your oracle database management system .Schema A and B.
And suppose your database design drive you to have a foreign key between table x in schema A to a table y in schema B. And this actually the same problem I faced in my system. I made a lot of search on the web until I found the solution.
In schema B you run the following grant access command :

Now you can run your foreign key add constrains


taking in mind that the schema is a user in oracle database .I wish i helped .