Enumerations for _Chem_shift_ref.External_ref_loc (An open enumeration) 
insert at center of a separate sample tube enumeration_text 
insert at center of experimental sample tube enumeration_text 
insert at outer edge of a separate sample tube enumeration_text 
insert at outer edge of experimental sample tube enumeration_text 
other enumeration_text 
separate tube (no insert) not similar to the experimental sample tube enumeration_text 
separate tube (no insert) similar to the experimental sample tube enumeration_text