DIXON, F. (1970). THE HARDY BOYS: THE SHATTERED HELMET. GROSSET & DUNLAP.
Lua i Stíl Chicago (17ú heag.)DIXON, FRANKLIN.W. THE HARDY BOYS: THE SHATTERED HELMET. USA: GROSSET & DUNLAP, 1970.
Lua MLA (9ú heag.)DIXON, FRANKLIN.W. THE HARDY BOYS: THE SHATTERED HELMET. GROSSET & DUNLAP, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.