Black Sun: Aryan Cults, Esoteric Nazism and the Politics of Identity, su culticstudiesreview.org. URL consultato il 12 dicembre 2023 (archiviato dall'url originale il 3 maggio 2006).
«Erich Halik, a Swiss engineer and a member of the Vienna circle of Fascists surrounding Wilhelm Landig (1909-1997), was the first to link the “Black Sun” roundel insignia with the esoteric SS. “The alchemical metaphor of sol niger [black sun] was said to represent occultation, blackening, a sinking into the mystery of self-discovery”»