I'm looking for a reference for the following result about the Pontryagin dual
Theorem: Let $G,H,K$ be three compact abelian groups such that $$0\rightarrow G\rightarrow H\rightarrow K\rightarrow 0$$ is a (short) exact sequence then $0\rightarrow \hat K \rightarrow \hat H \rightarrow \hat G\rightarrow 0$ is also exact.
Thanks!