Figure 9: Portions of the tensor-biscalar 
plane permitted by timing observations of
PSRs B1913+16, B1534+12, and B1855+09 up to
1992. Values lying above the curve labeled “a” are incompatible with the measured 
and
parameters for PSR B1913+16. The curves labeled “b” and “d” give the
allowed ranges of 
and 
for PSRs B1913+16 and B1534+12,
respectively, fitting for the two neutron-star masses as well as 
and 
, using data available
up to 1992. The vertical lines labeled “c” represent limits on 
from the SEP-violation test using
PSR B1855+09 [43]. The dot at (0,0) corresponds to GR. (Reprinted by permission
from Nature [133], Ⓒ 1992, Macmillan Publishers Ltd.)