I really love music that combines songs, or 'mashes' them together. It's just fun to hear some old favorites remixed, sampled and combined with other music for a new sound. ( Of course, if I'm not familiar with the original, then it's hard to tell what's being sampled, and what's original (if anything) !
Maybe those musical mashup bring a smile because we like deciphering mash-ups of another type - call them 'citation mashups '. A citation is like a map that leads you to a destination in the literature. Follow the path it describes and you'll get to the information you seek. Journal title, year, volume, issue, page... each helps you navigate through the information landscape. Follow them and voila! .... well, that's idea anyway. Most of the time the citation "map" works beautifully, but there are other cases where the map leaves you lost. You're stuck, and trouble is, you still want that article !
We often get requests for documents that are out there in the literature, but we don't have the correct map to lead us there. Sometimes we just just don't have all the information we need, and sometime the information we have is incorrect, and the citation is bad. For example, the author and journal title from one citation gets mixed up with the volume number and year from another citation. Surprisingly, many of these "citation mashups" come from documents that you'd expect to be well behaved, like patents.
Here's one: Webb, etal; Immunochemistry (1976) 5:131-208
It turns out this harmless-looking citation contains information from two other articles, cited correctly below. The relevant details are in bold.
1) Adv Immunol. 1966;5:131-208. Experimental allergic encephalomyelitis and autoimmune disease. Paterson PY.
2) Immunochemistry 13 (4): 333-337 1976. Molecular requirements involved in suppresion of EAE by synthetic basic copolymers of amino-acids. Author(s): Webb C, Teitelbaum D, Herz A, Arnon R, Sela M
So how does a citation mashup occur? And how is it perpetuated in the literature? Well, it turns out both of these articles appear in a bibliography by a third author. They also appear in a patent. Somewhere along the way, they got mashed together. And so now here we are, trying to find a copy of an article that doesn't exist, in that context, at least.
For some insight into the problem, enter a known citation mashup to a resource like ISI's Science Citation index and see if it doesn't produce a few hits. It turns out that once an article is improperly cited, it's likely to be improperly cited time and time again. The take home message here is one that most scholars are familiar with; if you read an article and discover a reference to a third party's work, you probably shouldn't cite that third party without getting a copy of the article and reviewing it yourself.
Which is why we provide a title page and copyright page standard with the articles we supply. Because you need to know your citation is correct, and the article appears in the literature as cited.