On the structure of elliptic curves over finite extensions of ${\mathbb{Q}}_p$ with additive reduction

Let $p$ be a prime and let $K$ be a finite extension of ${\mathbb{Q}}_p$. Let $E\mathrm{/}K$ be an elliptic curve with additive reduction. In this paper, we study the topological group structure of the set of points of good reduction of $E(K)$. In particular, if $K\mathrm{/}{\mathbb{Q}}_p$ is unramified, we show how one can read off the topological group structure from the Weierstrass coefficients defining $E$.