Indoor geolocation in the absence of direct path. - Kaveh Pahlavan; Ferit Ozan Akgül; Mohammad Heidari; Ahmad Hatami; John M. Elwell; Robert D. Tingley (IEEE Wirel. Commun., 2006)

A Nonlinear Code Tracking Filter for GPS-Based Navigation. - Donald E. Gustafson; John R. Dowdle; John M. Elwell; Karl W. Flueckiger (IEEE J. Sel. Top. Signal Process., 2009)