Iterator Pattern Code Review

class Program { static void Main(string[] args) { var family = new Tree( new Node(new Person("Tom", 1950), new Node(new Person("Peter", 1976), new Node(new Person("Sarah", 2000), null, new Node(new Person("James", 2002), null, null)), new Node(new Person("Robert", 1978), null, new Node(new Person("Mark", 1982), new Node(new Person("Carrie", 2005), null, null), null))), null) );
Console.WriteLine("Full Family"); foreach (Person p in family.Preorder) { Console.Write("{0} ", p); } Console.WriteLine("\n");
var selection = from p in family where p.Birth > 1980 orderby p.Name select p;
Console.WriteLine("Born after 1980 in alpha order"); foreach (Person p in selection) { Console.Write("{0} ", p); } Console.WriteLine("\n"); Console.Read(); } }