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International
Tables for Crystallography Volume G Definition and exchange of crystallographic data Edited by S. R. Hall and B. McMahon © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. G. ch. 2.6, p. 68
Section 2.6.6.1.18. ITEM_UNITS
a
Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers, The State University of New Jersey, Department of Chemistry and Chemical Biology, 610 Taylor Road, Piscataway, NJ 08854-8087, USA, and bSchool of Biomedical and Chemical Sciences, University of Western Australia, Crawley, Perth, WA 6009, Australia |
The ITEM_UNITS category holds a code that identifies the system of units in which a data item is expressed. The data item _item_units.code is a child of the item _item_units_list.code. Unit definitions are actually made in the ITEM_UNITS_LIST parent category. The item _item_units.code provides an indirect reference into the list of data-type definitions in category ITEM_UNITS_LIST. This indirect reference is provided as a convenience to avoid the redeclaration of the full data-type specification for each data item. The key item for this category is _item_units.name, which is defined in the parent category ITEM. Only one type of unit may be specified for a data item.
