Rozwiązania zadań Edhella Notatki
http://books.google.pl/books?id=S7d1pjJHsRgC&pg=PA75&lpg=PA75&dq=holladay+theorem+proof&source=bl&ots=2v27vXVZvL&sig=Wel-Tnp9hEfraV1WxJAeiIK-8LM&hl=pl&ei=vKoLS6ewNYzK_gbFh92WBA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CAsQ6AEwAQ#v=onepage&q=holladay%20theorem%20proof&f=false