| Name | Info | Provider | Link |
|---|---|---|---|
| subscription/membership/fee required | Elsevier Science | https://linkinghub.elsevier.com/retrieve/pii/S1470032803025527 | |
| Childbirth | free resource | MedlinePlus Health Information | https://medlineplus.gov/childbirth.html |
| subscription/membership/fee required | Wiley | https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=1470-0328&date=2003&volume=110&issue=10&spage=948 |