Как работать со связями многие-ко-многим, используя linq?

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public class Student
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<Course> Courses { get; set; }
}

public class Course
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<Student> Students { get; set; }
}

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List<Student> students = new List<Student>
{
    new Student { Id = 1, Name = "Студент 1" },
    new Student { Id = 2, Name = "Студент 2" },
    new Student { Id = 3, Name = "Студент 3" }
};

List<Course> courses = new List<Course>
{
    new Course { Id = 1, Name = "Курс 1" },
    new Course { Id = 2, Name = "Курс 2" },
    new Course { Id = 3, Name = "Курс 3" }
};

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students[0].Courses = new List<Course> { courses[0], courses[2] };
students[1].Courses = new List<Course> { courses[1] };
students[2].Courses = new List<Course> { courses[0], courses[1] };

courses[0].Students = new List<Student> { students[0], students[2] };
courses[1].Students = new List<Student> { students[1], students[2] };
courses[2].Students = new List<Student> { students[0] };

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int studentId = 1;
var selectedCourses = students.Where(s => s.Id == studentId)
    .SelectMany(s => s.Courses);