1. Radiopropagación:
http://www.4shared.com/document/Kbu4Y_K2/Articulo_IEEE_-_Analysis_of_th.html
Parte I:
http://www.4shared.com/document/D6KpqcVD/Paper-Norton-1937-Primera-Part.html
Parte II:
http://www.4shared.com/document/kbt7U9jv/Paper-Norton-1937-SegundaParte.html