In this paper, we build an exact sequence relating the group SK_2 of a
biquaternion algebra - kernel of the reduced norm - over a field F
with Galois cohomology groups of F. This exact sequence is an analogue
for K_2 of an exact sequence from M. Rost for K_1. This paper contains
the proofs of the theorems stated without proof in the preprint 616.
Note: I suggest reading the pdf file if possible, because some people
reported me problems reading the drawings in the dvi file on some
systems.
The dvi file is readable if the files SSpconiveau.pstex and
SSppoids.pstex are downloaded, too -- [drg].
This paper provides the proofs of the results announced in preprint 616.