Anders Fager's "Collected Swedish Cults" features a Stockholm-based coterie known as "The Carcosa Foundation" that worships Hastur.
In his Dark Border novels Paul uses a lot of names that would be familiar to fans of both his sister and H P Lovecraft, such as Carcosa, Hastur, Hali and Hyades amongst others.
I found myself faced by names and terms that I had heard elsewhere in the most hideous of connections — Yuggoth, Great Cthulhu, Tsathoggua, Yog-Sothoth, R'lyeh, Nyarlathotep, Azathoth, Hastur, Yian, Leng, the Lake of Hali, Bethmoora, the Yellow Sign, L’mur-Kathulos, Bran, and the Magnum Innominandum .