1. G.P.S. Occhialini, C.F. Powell, Nature 159, 186(1947).
2. D. Horvath, R.M. Lambrecht, Exotic Atoms — a bibliography 1939 – 1982, Elsevier, 1984.
3. R. Bacher, P. Blüm, D. Gotta, K. Heitlinger, M. Schneider, J. Missimer, L.M. Simons, Preprint PR-88–14, PSI, Villigen, Switzerland, 1988.
4. E. Köhler, R. Bergmann, H. Daniel, P. Ehrhart, F.J. Hartmann, Nucl. Instr. Meth. 187, 563 (1981).
5. H. Daniel, F.J. Hartmann, E. Köhler, U. Beitat, J. Riederer, Archaeometry 29, 1 (1987).