static <A extends Concept> Cl<A> nuLike conceptsSortedByFieldCI(Class<A> c, S field) {
  ret conceptsSortedByFieldCI(db_mainConcepts(), c, field);
}

static <A extends Concept> Cl<A> conceptsSortedByFieldCI(Concepts concepts, Class<A> c, S field) {
  // indexed
  IFieldIndex<A, O> index = concepts.getCIFieldIndex(c, field);
  if (index instanceof IConceptCounter)
    ret index.allConcepts();
    
  // sort manually
  ret sortedByFieldIC(field, concepts.list(c));
}