The Author field is interpreted by bibtex as an author name, and
formatted according to that interpretation. In short: the output you
get is correct, it's your expectations that are wrong. If you want to
pass a string as formatted as an author, you should put it in an extra
pair of braces.
I cannot get the correct output whenever I enter in the author field
something like:
The Clopidogrel in unstable angina to prevent recurrent events trial
investigators.
this is what I get in pdf with a vancouver.bst style
in unstable angina to prevent recurrent events trial investigators
The
