| Name | Info | Provider | Link |
|---|---|---|---|
| subscription/membership/fee required | Nature Publishing Group | https://doi.org/10.1038/nature06718 | |
| subscription/membership/fee required | Ovid Technologies, Inc. | http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=18354396.ui |