| Name | Info | Provider | Link |
|---|---|---|---|
| subscription/membership/fee required | Elsevier Science | https://linkinghub.elsevier.com/retrieve/pii/00006396-199912010-00009 | |
| subscription/membership/fee required | Ovid Technologies, Inc. | http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=10568854.ui | |
| subscription/membership/fee required | Wolters Kluwer | https://doi.org/10.1016/S0304-3959(99)00150-5 |