The noncovariant duality symmetric action put forward by Schwarz and Sen is quantized by means of the Dirac brackets quantization procedure. The resulting quantum theory is shown to be, nevertheless, relativistically invariant. [S0556-2821(97)01106-5].
Physical Review. D, Particles and fields. Woodbury. Vol. 55, n. 8 (Apr. 1997), p. 5136-5139