Ludendorff, M. (1954). The origin and nature of the soul. Hohe Warte.
Lua i Stíl Chicago (17ú heag.)Ludendorff, Mathilde. The Origin and Nature of the Soul. Pähl: Hohe Warte, 1954.
Lua MLA (9ú heag.)Ludendorff, Mathilde. The Origin and Nature of the Soul. Hohe Warte, 1954.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.