  Recently, several discussions on the possible observability of 4-vector
potential have been published in literature. Furthermore, several authors
recently claimed existence of the helicity=0 electromagnetic field. We
re-examine the theory of antisymmetric tensor field and 4-vector potentials. We
study the massless limits too. In fact, a theoretical motivation for this
venture is old papers of Ogievetskii and Polubarinov, Hayashi, and Kalb and
Ramond, which are widely accepted by physics community. This paper is based on
two poster presentations "About the Longitudinal Nature of the Antisymmetric
Tensor Field after Quantization" and "Normalization and m->0 Limit of the Proca
Theory" at the Workshop "Lorentz Group, CPT and Neutrinos" (Zacatecas, Mexico,
June 23-26, 1999).
