On Infocentre (the link you provided), the APIs are usually provided in the References subsection, for each product. I don't think you'll find a more complete list than that anywhere else.
If you mean resources on WebSphere Application Server, you can try searching for that on IBM Redbooks, e.g.: http://www.redbooks.ibm.com/redbooks/pdfs/sg247957.pdf
Devworks also has quite a few papers explaining concepts/providing examples for IBM products. http://www.ibm.com/developerworks/websphere/library/