1. A.B. Denison, H. Graf, W. Kündig, P.F. Meier, Helvetica Physica Acta 52 (1979) 460
2. P.F. Meier, in: Muons and Pions in Materials Research, ed. by J. Chappert and R.I. Grynszpan (North-Holland, Amsterdam 1984), p. 77.
3. W.J. Kossler, A.T. Fiory, D.E. Murnick, C.E. Stronach, W.F. Lankford, Hyperfine Interactions 3 (1977) 287
4. V.G. Grebinnik, I.I. Gurevich, A.I. Klimov, V.N. Majorov, A.P. Manych, E.V. Mel'nikov, B.A. Nikol'skiî, A.V. Pirogov, A.N. Ponomarev, V.I. Selivanov, V.A. Suetin, V.A. Zhukov, Hyperfine Interactions 6 (1979) 103
5. V.G. Grebinnik, I.I. Gurevich, V.A. Zhukov, I.G. Ivanter, A.I. Klimov, A.P. Manych, E.V. Mel'nikov, B.A. Nikol'skiî, A.V. Pirogov, A.N. Ponomarev, V.I. Selivanov, V.A. Suetin, and S.V. Fomichev, JETP Lett. 28 (1978) 423