Distinct пользовательского объекта

class Person : INameAndCopy, IEquatable<Person>
  {
    private string _Name;
    private string _Surname;
    DateTime _Birth;
 
    public Person(string name, string surname, DateTime birth)
    {
      _Name = name;
      _Surname = surname;
      _Birth = birth;
    }
 
    public Person()
    {
      _Name = "Иван";
      _Surname = "Болван";
      _Birth = new DateTime(2020, 8, 9);
    }
 
    public string Name
    {
      get => _Name;
      set => _Name = value;
    }
 
    public string Surname
    {
      get => _Surname;
      set => _Surname = value;
    }
        
    public DateTime Birth
    {
      get => _Birth;
      set => _Birth = value;
    }
 
    public int ChangeYear
    {
      get => _Birth.Year;
      set => _Birth.AddYears(-_Birth.Year + value);
    }
 
    public virtual string ToShortString() =>
      $"Имя: {_Name}\t Фамилия: {_Surname}";
 
    public override string ToString() =>
      $"{ToShortString()}\t" +
      $"ДР: {_Birth.ToShortDateString()}";
 
    public bool Equals(Person other)
    {
      if (other == null)
        return false;
 
      if (object.ReferenceEquals(this, other))
        return true;
 
      if (this.GetType() != other.GetType())
        return false;
 
      return other.Surname == _Surname &&
        other.Name == _Name && other.Birth == _Birth;
    }
 
    public override bool Equals(object obj)
    {
      if (obj == null)
        return false;
 
      if (ReferenceEquals(this, obj))
        return true;
 
      if (this.GetType() != obj.GetType())
        return false;
 
      return Equals(obj as Person);
    }
 
    public override int GetHashCode() =>
      _Name.GetHashCode() + _Surname.GetHashCode() + _Birth.GetHashCode();
 
    public static bool operator ==(Person p1, Person p2) =>
      p1.Equals(p2);
 
    public static bool operator !=(Person p1, Person p2) =>
      !(p1 == p2);
 
    public object Clone() =>
      new Person
      { _Name = this._Name, _Surname = this._Surname, _Birth = this._Birth };
 
  }

//нет публикаций
    public IEnumerator<Person> GetEnumerator()
    {
      foreach (var paper in _Publications)
      {
        if (!_Members.Contains(paper.Author))
          yield return paper.Author;
      }
    }
 
    public IEnumerator<Paper> GetEnumerator(int year)
    {
      foreach(var paper in _Publications)
      {
        if (DateTime.Today.Year - paper.Date.Year < year)
          yield return paper;
      }
    }
 
    // дополнительное задание
    #region
    // авторы c публикациями
    public IEnumerator GetEnumerator() =>
       new ResearchTeamEnumerator(_Publications);
 
    public IEnumerator<Person> AuthorsMoreThen1Paper()
    {
      foreach (var author in _Members)
        if (_Publications.Count(p => p.Author == author) > 1)
          yield return author;
    }
 
    public IEnumerator PapersForLastYear()
    {
      foreach (var paper in _Publications)
        if (DateTime.Now.Subtract(paper.Date).Days < 365)
          yield return paper;
    }
    #endregion