Two comments: 1. I think that in defining citations it is important that the order of the authors and editors be explicitly defined. This can be handled by adding to data items to the dictionary _citation_author.ordinal and _citation_editor.ordinal. An possible definition for _citation_author.ordinal is given below. save__citation_author.ordinal _item_description.description ; This data item defines the position of the author's name in the list of authors on a citation. ; _item.name '_citation_author.ordinal' _itme.mandatory_code yes _item.category_id citation_author _item.type.code integer save_ 2. In the example mmcif DDF040 provided on the server, there is an error in the ENTITY section. The loop defines five data items but only three values are provided with the formula_weight and details missing. Best regards, Eldon Ulrich