@article{Lawrence_2001,
 author = {Lawrence, Steve},
 year = {2001},
 title = {Free online availability substantially increases a paper's impact},
 url = {10.1038/35079151">http://dx.doi.org/10.1038/35079151},
 urldate = {2015-05-16},
 pages = {521},
 volume = {411},
 number = {6837},
 journal = {Nature},
 doi = {10.1038/35079151}
}