sort with a tab as separator

[phd_ivo at gsbacd.uchicago.edu]

How do I indicate to sort that my field-separation character is the tab (^I)?
I know that there is a tab option (-t) in sort, but I don't know how to specify 
^I ( or \t, for that matter).. No, the default is not this tab, but any
whitespace character according to my documentation.

Thanks for any help.

/ivo welch	ivo at next.agsm.ucla.edu