Extensions of the Stein-Tomas theorem

We prove an endpoint version of the Stein-Tomas restriction theorem, for a general class of measures, and with a strengthened Lorentz space estimate. A similar improvement is obtained for Stein's estimate on oscillatory integrals of Carleson-Sj\"olin-H\"ormander type and some spectral projection operators on compact manifolds, and for classes of oscillatory integral operators with one-sided fold singularities.