How to choose OD layers
H. Grell · Acta Crystallographica Section A Foundations of Crystallography · 1984
A method for choosing OD layers in a structure is given. For any structure one of four cases is possible: I. the structure cannot be interpreted as an OD structure consisting of layers; 2. the OD layers are uniquely determined; 3. the limits between OD layers may be changed with keeping the OD groupoid family; and 4. the limits may be changed with changing the OD groupoid family.