              Data items in the STRUCT_SHEET_ORDER category record details\
               about the order of the residue ranges that form a beta sheet.\
               All order linkages are pairwise, and the specified pairs are\
               assumed to be adjacent to one another in the sheet. These data\
               items are an alternative to the STRUCT_SHEET_TOPOLOGY data\
               items, and they allow for the formal description of all manner\
               of sheets.