by Teunissen, P.J.G., Jonkman, N.F., Joosten, P., Tiberius, C.C.J.M.
Published in IEEE 2000. Position Location and Navigation Symposium (Cat. No.00CH37062) (2000)

by de Jong, C.D., van der Marel, H., Jonkman, N.F.
Published in Physics and chemistry of the earth. Part A, Solid earth and geodesy (2001)