Incommensurate structures and radiation damage in Rb<sub>2</sub>V<sub>3</sub>O<sub>8</sub> and K<sub>2</sub>V<sub>3</sub>O<sub>8</sub> mixed-valence vanadate fresnoites
Acta crystallographica. Section B, Structural science, crystal engineering and materials./Acta crystallographica. Section B, Structural science, crystal engineering and materials