Armbruster T , Krivovichev S V , Weber T , Gnos E , Organova N N , Yakovenchuk V N , American Mineralogist , 89 (2004) p.1655-1666, Origin of diffuse superstructure reflections in labuntsovite-group minerals, Sample A2 at T = 22 deg C, Locality: Khibiny alkaline complex, Kola peninsula, Russia