Same. Thought I had a copy of Uthark [1][2] on my shelf too but alas I seem to have only retained Svartkonst [3] during the tragic downsizing of my library.

[1] https://archive.org/details/karlsson-thomas-uthark-nightside...

[2] https://www.84cxrarebooks.com/pages/books/090763/t-ketola-th...

[3] https://www.miskatonicbooks.com/product/thursakyngi-iv-svart...