Searching `Birch and Swinnerton-Dyer' by Google, there are two short preprints on this theme:[Yongxiong Li, Yu Liu, Ye Tian](https://arxiv.org/abs/1605.01481) and [K.Morita](https://kazuma-morita.jimdo.com/app/download/12516883590/BSD.conjecture-congruent.number.problem.pdf?t=1495168671).