  Generalizing the 't Hooft and Veltman method of unitary regulators, we
demonstrate for the first time the existence of local, Lorentz-invariant,
physically motivated Lagrangians of quantum-electrodynamic phenomena such that:
(i) Feynman diagrams are finite and equal the diagrams of QED but with
regularized propagators. (ii) N-point Green functions are causal. (iii)
S-matrix relates only electrons, positrons and photons, is unitary and
Lorentz-invariant, and conserves charge and total four-momentum.
