Christian Schwerdtfeger, Stärkstes Erdbeben seit 1955 ("The Strongest Earthquake Since 1955"), RP Online, 24 July 2009 (German), retrieved 23 May 2010.
Johann Peter Joseph Monheim, Die Heilquellen von Aachen, Burtscheid, Spaa, Malmedy und Heilstein in ihren historischen, geognostischen, physischen, chemischen und medizinischen Beziehungen, Aachen: J.A. Mayer, 1829, p. 260 (German).
Klaus-G. Hinzen and Sharon K. Reamer, "Seismicity, seismotectonics, and seismic hazard in the northern Rhine area", Geological Society of America special papers, Abstract, 29 November 2006, retrieved 29 May 2010, refers to a maximum magnitude of 7.0.
Baugeschichte (History of the Building), Wallfahrtskirche Maria Zell, 4 September 2006 (German), retrieved 3 June 2010. The church has been damaged by other earthquakes before and since.