Entity framework 6: how to avoid circular reference

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What are the possibilities to avoid circular reference with Entity Framework 6 during JSON serialization with ASP.NET Web API?

I generated a edmx (Entity Data Model) file for Entity Framework 6, database first. I try to build an API with ASP.NET Web API. When I try to return my JSON object in my controllers I get a runtime exception of serialization because of circular reference.

Indeed when I double check my database and my entities I see one of my entity contains a list another entity that contain a list of my previous entity. let say I have a book entity that contains authors and each author entity contains a list of books. This is something common with relative database but impossible to resolve in JSON serialization (or impossible to resolve for the .NET serializer).

I don't want to change my database but I'm ready to break the wrong list into my entities or edmx file. What can I do?

What I have tried:

I already tried the solution that consist of creating new models or entities and using a mapping tool (http://www.codeproject.com/Articles/292970/Avoiding-Circular-Reference-for-Entity-in-JSON-Ser or the solution explained by by Shawn Wildermuth on Plurasight).

This solution sounds more like a workaround than a real solution. It should exist something in edmx file or in Entity Framework to tell the JSON serializer what can cause circular reference and what to serialize, right?