My source was the Animal and Plant Health Inspection Service.
The link was http://www.aphis.usda.gov/lpa/issues/bse/bse-overview.html but I can't seem to get it to work anymore. I'm not sure if they retracted the statement or if it's just because many of the links on their website seem FUBAR'd at the moment (clicking on About APHIS from their homepage works, but not from their Search page).
I found a link to a George A Venters article here as well as here.
I also base my conclusions on a stunning lack of increase of vCJD that was predicted by the CDC, particularly in proportion to the outbreak of BSE in England. Doubly so in places that consider cow brains to be a delicacy (which would result in maximal exposure to BSE).
I found one article here that was an interesting read, but many of its reference links are now dead. It was an early 2004 article, so perhaps things have changed in the past year. Which would also explain my ignorance since I don't follow on the BSE hoopla much anymore.
In fact, given what I've learned of BSE and its suspected transmittability, I'd probably still eat a steak from a cow in spite of knowledge that it had BSE, since even the CDC comments that muscle has never been reproducibly shown to contain the infectious agent in any form of spongiform encephalopathy, whatever the affected species.
Having said that, it's possible new research has changed things, and even then, you could still argue through semantics that vCJD isn't exactly the same as BSE, so you don't get BSE