SAP Standard Cubes

Hello Colleagues,

Could anyone please let me know where I can find the SAP standard business content cubes (may be some link on saphelp, or some other site, or some table, transaction...)?

For ex: I have the purchasing cube ZS590 which is custom built. I need to find out how it differ from SAP standard cube. And so I am looking for this.

Your help will be appreciated...

Regards