Gaya APA
Blavatsky, H, P.
(1983).
Der Schlüssel zur Theosophie.
.
Graz:
Adyar.
Gaya MLA
Blavatsky, Helena, Petrowna..
"Der Schlüssel zur Theosophie. ".
Graz:
Adyar,
1983.
Buku.