In this paper1 the authors cite the HVZ theorem2 saying that it follows from the method used by M. Reed & B. Simon without modifications; I don't really understand this point. Is there anyone who have tried to prove it?
1. Mogilner, A. I.; Shermatov, M. H., Binding of two fermions with a third different particle by a point interaction, Physics Letters A, Volume 149, Issue 7-8, 1990, p. 398-400.
2. (named after W. Hunziker, C. van Winter und G.M. Zhislin)