Small-eccentricity binary pulsars with white dwarf companions provide
excellent test laboratories for various effects predicted by alternative
theories of gravity, in particular tests for the emission of gravitational
dipole radiation and the existence of gravitational Stark effects. We will
present new limits to these effects. The statistical analysis presented here,
for the first time, takes appropriately care of selection effects.Comment: 4 pages, to be published in Proc. of IAU Colloq. 177, "Pulsar
Astronomy - 2000 and Beyond", eds. M. Kramer, N. Wex & R. Wielebinsk
