Burgener J.A. (2015). 23.4° Massive elliptical comet impact craters on Earth.
Monika Kumlehn de Mamani & Ingrid Grambow IMPAKTNAMEN: Namen der [Meteorite; Impakte/Krater; Boliden/Fireballs; Tektite] im Sonnensystem.(2016)

23.4° features in Europe and Asia (Burgener J.A., 2015).