It is rare for documents to be systematic in their description of the relationships between problems. Relationship networks have to be built up from several different sources. Often it is not clear whether the relationship applies for the whole of a problem hierarchy or for only some component part. There is a continuing effort to refine such networks, but even when a relationship is contentious the practice is to retain the relationship provisionally rather than exclude it and lose a potential link. This said, it is generally easier to criticize errors of commission than to undertake the extra effort to remedy errors of omission.
More recent publications are preferable, if available.
However, publications produced when the problem was first recognized may contain better articulations of the dimensions of the problem. References should be cited within the entry matching their content, not at a narrower or broader level. The title of a pertinent publication may not necessarily correspond to the problem name. A seemingly pertinent publication title may disguise a totally unfocused content. If there are numerous organizations concerned with a problem, it is best to cite an umbrella body rather than any one.