Retrieving data from N:N relationship

Hello,

I created a relationship of N:N between two entities - Student and Course.

On the Student form I have a sub-grid that lists all of the courses the student takes, and on the Course form I have a sub-grid that lists all of its students.  I do not use any Lookup fields in my forms.

I'd like to retrieve all of the courses a student has.

Is it possible without the use of a Lookup?

I've tried using LINQ but got confused. 

I'm currently trying to use QueryExpression.

I'd appreciate help.

Thank you.