New Binary and Millisecond Pulsars from Arecibo Drift-Scan Searches
  We discuss four recycled pulsars found in Arecibo drift-scan searches. PSR J1944+0907 has a spin period of 5.2 ms and is isolated. The 5.8-ms pulsar J1453+19 may have a low-mass companion. We discuss these pulsars in the context of isolated millisecond pulsar formation and the minimum spin period of neutron stars. The isolated 56-ms pulsar J0609+2130 is possibly the remnant of a disrupted double neutron star binary. The 41-ms pulsar J1829+2456 is in a relativistic orbit. Its companion is most likely another neutron star, making this the eighth known double neutron star binary system. 
M. A. McLaughlin, D. R. Lorimer, D. J. Champion, Z. Arzoumanian, D. C.   Backer, J. M. Cordes, A. S. Fruchter, A. N. Lommen ...