Bibliographic coupling is a term coined by Kessler (doi:10.1002/asi.5090140103) in 1963 as a measure of similarity between documents. If two documents, A and B, cite a third, C, then A and B are coupled.I'm interested in extending this to data, such as DNA sequences and specimens. In part this is because within the challenge dataset I'm finding cases where authors cite data, but not the paper publishing the data.