1. R. M. Steffen and H. Frauenfelder, in Perturbed Angular Correlations, edited by E. Karlsson, E. Matthias, and K. Siegbahn (North-Holland, Amsterdam, 1964), pp. 1–89.
2. H. Frauenfelder and R. M. Steffen, in Alpha- Beta- and Gamma-Ray Spectroscopy, edited by K. Siegbahn (North-Holland, Amsterdam, 1965), pp. 1997–1198.
3. Perturbed Angular Correlation of Gamma Rays
4. The g-factor of the 2.083 MeV 4+ state of Ce140