Indoor and Outdoor Positioning in Mobile Environments - a Review and some Investigations on WLAN-Positioning. - Ralf Bill; Clemens H. Cap; Martin Kofahl; Thomas Mundt (Ann. GIS, 2004)

Location Concepts for the Web. - Martin Kofahl; Erik Wilde (Weaving Services and People on the World Wide Web, 2008)

The locative web. - Erik Wilde; Martin Kofahl (LocWeb, 2008)