in comparing reference unification to reference linking, the authors found that reference linking yield similar result as that of reference unification. an investigative study was conducted by these authors at chinese science citation database (cscd) of national science library (nsl) of the chinese academy of sciences (cas), it was found that there were three inhibiting elements in invoking a reference unification solution and the same is true for a reference linking solution. firstly, it was difficult to define a minimum set of data elements for matching. secondly, it had a problem of data inaccuracy and/or data incompleteness. thirdly, it was hard to determine an appropriate linking result that produced the desired document for the user. thus these authors suggest that getting digital object identifier (doi) for each journal article is a good way to bring about reference unification and also to improve metadata quality simultaneously at the same time. therefore, doi has a pivotal role to play in terms of bringing about reference unification and/or a reference linking.