1. K.L.Kowalski in Lecture Notes in Physics 87, 393 (1978); Nucl.Phys. A414, 465(1984); F.S.Levin, Nucl.Phys. A353, 143(1981).
2. O.A.Yakubovsky, Yad.Fiz. 5, 1312 (1967) [Sov.J.Nucl.Phys.5,937(1967)]
3. P.Grassberger and W.Sandhas, Nucl.Phys. B2, 181 (1967); E.O.Alt, P. Grassberger and W.Sandhas, Joint Institute for Nuclear Research Report no E4-6688(1972).
4. E.O.Alt, P.Grassberger and W.Sandhas, Phys.Rev.C1, 85 (1970).
5. A.C.Fonseca in Few-Body Methods: Principles and Applications, edited by T.K.Lim, C.C.Bao, D.P.Hou and H.S.Huber [World Scientific, Singapore Singapore 1986)