Fernández-Rañada, Antonio2023-06-212023-06-211980-11-150556-282110.1103/PhysRevD.22.2416https://hdl.handle.net/20.500.14352/64905© 1980 The American Physical Society. We are very indebted to Dr. M. Ramón, Dr. M.A. Rodríguez, and Dr. J. Usón for discussions. This paper was partly supported by Junta de Energía Nuclear, Madrid.It is shown that the noncausality of the Rarita-Schwinger equation in an external electromagnetic field can be avoided by the substitution of a subsidiary constraint by a subsidiary differential equation. As the number of degrees of freedom increases, the theory represents two kinds of articles with spin l/2 and spin 3/2. Some consequences are studied.engjournal articlehttp://dx.doi.org/10.1103/PhysRevD.22.2416http://journals.aps.orgopen access537ElectricidadElectrónica (Física)2202.03 Electricidad