Optionally, select the criterion used to determine the
diffraction-limit surface for the data:
NOTE: the 4-character PDB ID (case-insensitive)
entered in the box above, optionally for multiple datasets with '-N'
appended to indicate the dataset ordinal (i.e. '-1' for the first
dataset, '-2' for the second etc.), MUST have intensities
(unmerged or merged) and/or observed structure amplitudes (both with
standard uncertainties) deposited.  Calculated structure factors,
map coefficients, phases, free R flags etc. are all ignored if
present.  For the Table 1 and datasets pages only the first 4
characters are used.