GEOFON

No year given for re-used network code 6A. Use a year to disambiguate:

• 6A:2008 (2008–2009) Rohrbach/Vogtland Seismic Array, U. Potsdam
• 6A:2010 (2010–2012) WALPASS Network, Namibia
• 6A:2020 (2020–2035) ICDP-EGER-University of Potsdam Experimental 3D-3C Array

Or choose from the complete list.