  We have searched 92 unidentified sources from the FIRST and NVSS radio
catalogs for pulsations at 610 MHz. The selected sources are bright, have no
identifications, are unresolved and have significant linear polarization. Our
search was sensitive to sub-millisecond pulsations from pulsars with a large
range of dispersion measures. We have detected no radio pulsations from these
sources and conclude that they are unlikely to be a population of previously
undetected pulsars.
