Martin Alan DeWitt Bakker, B. L. G., DeWitt, M. A., Ji, C. R., & Mishchenko, Y. (2005). Restoring the equivalence between the light-front and manifestly covariant formalisms. PHYSICAL REVIEW D, 72(7). https://doi.org/10.1103/physrevd.72.076005 DeWitt, M. A., Choi, H. M., & Ji, C. R. (2005, June). Scalar mesons in the light-front quark model. FEW-BODY SYSTEMS, Vol. 36, pp. 83–86. https://doi.org/10.1007/s00601-004-0082-y DeWitt, M. A., Choi, H. M., & Ji, C. R. (2003). Radiative scalar meson decay in the light-front quark model. PHYSICAL REVIEW D, 68(5). https://doi.org/10.1103/physrevd.68.054026