Символ $ в json ответе (ASP.NET WebAPI)

Есть ASP.NET Web API Есть контроллер на получение данных

Код:

 public class GetCompaniesController : ApiController
{
    private ApplicationDbContext db = new ApplicationDbContext();
    // GET: api/GetCompanies
    public IHttpActionResult GetCompanies()
    {
        var companies = db.Companies.ToList();
        return Ok(new { results = companies });
    }

Но возвращает он так данные

{"$id":"1","results":[{"$id":"2","Company":{"$id":"3","Clients":[{"$id":"4","Company":{"$ref":"3"},"Id":20,"Email":"nemesises@live.com","UserName":"Евгений","Position":"Developer","Password":"Dontoretto23","From":null,"Subject":null,"Body":null,"CompanyID":20}],"Vacancies":[{"$ref":"2"},{"$id":"5","Company":{"$ref":"3"},"Interwiers":[],"InvitationMails":[],"Interviews":[],"VacancyId":2,"VacancyName":"Тест      ","CompanyID":20},{"$id":"6","Company":{"$ref":"3"},"Interwiers":[],"InvitationMails":[],"Interviews":[],"VacancyId":3,"VacancyName":"Менеджер  ","CompanyID":20},{"$id":"7","Company":{"$ref":"3"},"Interwiers":[],"InvitationMails":[],"Interviews":[],"VacancyId":4,"VacancyName":"Грузчик   ","CompanyID":20}],"CompanyID":20,"CompanyName":"Фокстрот"},"Interwiers":[],"InvitationMails":[],"Interviews":[{"$id":"8","Vacancy":{"$ref":"2"},"Interview_Id":7,"Greeting":"Добрый день!","Detail":"Пройдите интервью","VacancyId":1},{"$id":"9","Vacancy":{"$ref":"2"},"Interview_Id":8,"Greeting":"sdfsdfsdfsdfsdf","Detail":"sdfsdfsdf","VacancyId":1},{"$id":"10","Vacancy":{"$ref":"2"},"Interview_Id":9,"Greeting":null,"Detail":null,"VacancyId":1},{"$id":"11","Vacancy":{"$ref":"2"},"Interview_Id":10,"Greeting":null,"Detail":null,"VacancyId":1},{"$id":"12","Vacancy":{"$ref":"2"},"Interview_Id":11,"Greeting":null,"Detail":null,"VacancyId":1},{"$id":"13","Vacancy":{"$ref":"2"},"Interview_Id":12,"Greeting":null,"Detail":null,"VacancyId":1},{"$id":"14","Vacancy":{"$ref":"2"},"Interview_Id":13,"Greeting":null,"Detail":null,"VacancyId":1}],"VacancyId":1,"VacancyName":"Менеджер  ","CompanyID":20},{"$ref":"5"},{"$ref":"6"},{"$ref":"7"}]}

Ка убрать символы?