Using the most recent atmospheric neutrino data, as well as short-baseline,
long-baseline and tritium beta -decay data we show that the joint interpre
tation of the LSND, solar and atmospheric neutrino anomalies in (3 + 1) ste
rile neutrino schemes is severely disfavored, in contrast to the theoretica
lly favored (2 + 2) schemes. (C) 2001 Elsevier Science BN. All rights reser
ved.