sortBy: An ST_SortBy ([ISO/IEC29500-1:2011] section 18.18.72) attribute that specifies how the cells in a range are sorted.
ref: An ST_Ref ([ISO/IEC29500-1:2011] section 18.18.62) attribute that specifies the row (2) or column (2) to which this sort condition applies. This value MUST be contained within the ref in the sortState ([ISO/IEC29500-1:2011] section 18.3.1.92) element that precedes this element. If the sortState.columnSort attribute that precedes this element is "false", this value specifies the column (2) to which this sort condition applies and there MUST be only a single column (2) specified by ref. If the sortState.columnSort attribute that precedes this element is "true", this value specifies the row (2) to which this sort condition applies and there MUST be only a single row (2) specified by ref.
