Poly[[diaqua(μ<sub>2</sub>-4,4′-dipyridyl sulfide-κ<sup>2</sup><i>N</i>:<i>N</i>′)(4,4′-dipyridyl sulfide-κ<i>N</i>)(2-hydroxy-5-sulfonatobenzoato-κ<i>O</i><sup>1</sup>)nickel(II)] dihydrate]
Acta crystallographica. Section E