  Radio timing observations of millisecond pulsars (MSPs) in support of Fermi
LAT observations of the gamma-ray sky enhance the sensitivity of high-energy
pulsation searches. With contemporaneous ephemerides we have detected gamma-ray
pulsations from PSR B1937+21, the first MSP ever discovered, and B1957+20, the
first known black-widow system. The two MSPs share a number of properties: they
are energetic and distant compared to other gamma-ray MSPs, and both of them
exhibit aligned radio and gamma-ray emission peaks, indicating co-located
emission regions in the outer magnetosphere of the pulsars. However, radio
observations are also crucial for revealing MSPs in Fermi unassociated sources.
In a search for radio pulsations at the position of such unassociated sources,
the Nan\c{c}ay Radio Telescope discovered two MSPs, PSRs J2017+0603 and
J2302+4442, increasing the sample of known Galactic disk MSPs. Subsequent radio
timing observations led to the detection of gamma-ray pulsations from these two
MSPs as well. We describe multiwavelength timing and spectral analysis of these
four pulsars, and the modeling of their gamma-ray light curves in the context
of theoretical models.
