21
Argitaratua 1976
Full text available from ABI/INFORM Global: 01/01/2004 to present
Baliabide elektronikoa Aldizkako argitalpena
23
Full text available from Middle East Newsstream: 10/06/2009 to present
Baliabide elektronikoa Aldizkako argitalpena
29
Full text available from Linguistics Database: 01/01/2004 to present
Baliabide elektronikoa Aldizkako argitalpena
30
Argitaratua 1989
Full text available from Earth, Atmospheric & Aquatic Science Database: 01/01/1998 to present
Baliabide elektronikoa Aldizkako argitalpena
36
Argitaratua 2002
Full text available from Canadian Business & Current Affairs Database: 06/01/2012 to present
Government Document Baliabide elektronikoa Aldizkako argitalpena