Referencing Internet Source used

How do I source the following in a term paper. I found an Excel data sheet on and the Excel data in turn references World Almanac 2005 data. When I reference this should I reference the fact the it is World Almanac 2005 data but that it found by way of another website? What format string would I use to reference this? Thanks.

What citation style?

Apart from that, I’d likely cite it as a web page, noting the access date and all. Also, I recommend a citation manager like Zotero (Firefox plugin), refworks/endnote (these would be subscription though you university library) or the like - as well as possibly (this site may not be correct for all citation styles: check it against your citation sourcebook).