Citation: Dg. Hellier et al., CHEMISTRY OF THE S=O BOND .13. STRUCTURES OF ISOMER-1(I) AND ISOMER-2(II) OF 4-METHYL-1,3,2-DIOXATHIANE 2-OXIDE AND 1,3,2-DIOXATHIEPANE 2-OXIDE(III) AT 256-K, 240-K AND 228-K, Acta crystallographica. Section B, Structural science, 52, 1996, pp. 505-508