(1968). The World Book Encyclopedia E, volume 6. USA.
Chicago Style aipamenaThe World Book Encyclopedia E, Volume 6. USA, 1968.
MLA aipamenaThe World Book Encyclopedia E, Volume 6. USA, 1968.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.
(1968). The World Book Encyclopedia E, volume 6. USA.
Chicago Style aipamenaThe World Book Encyclopedia E, Volume 6. USA, 1968.
MLA aipamenaThe World Book Encyclopedia E, Volume 6. USA, 1968.