In citations, how to find out if it's a compound name? I have a paper that I want to cite in my own work, in the form
"J. Wayne" (for John Wayne) in the bibliography part of the paper and Wayne in the body of the paper.

The full name of the author appears on the paper as Aaaa Bbbb Cccc, and is typically a non-western name.
Say, consider something like John Fitzgerald Kennedy, but let's assume you never heard of them, and they obviously are from a different culture, and you don't know if their last-name is Kennedy or Fitzgerald Kennedy.

Should I note it in my Bibtex file as Kennedy, John Fitzgerald or
Fitzgerald Kennedy, John ? This will change things when printed with last-name only, it will appear either as Kennedy or Fitzgerald Kennedy.

So, more generally, is there an academic naming convention for this kind of situation ?
Edit: To be more precise, what I want to know is if there is a standardized way for an author with such a name to sign his paper, for example Aaaa Bbbb-Cccc, so no ambiguity is left for the reader. Or for the reader, if one has a guaranteed way to know this (seems not).

I must add that I have seen the considered author cited as Bbbb or as Cccc, one of these being obviously incorrect (even both could be).
The convention, inasmuch as one exists, is:


  Write the name the way the individual wants it to be written.


For example, one of my co-authors has four names: 


  (First Name) (Middle Name) (Adopted Married Name) (Given Last Name) 


but chooses to use 


  (First Initial). (Middle Name) (Adopted Initial). (Last Name)


as his "formal" academic name. 

As a more concrete example of this phenomenon, this is a significant issue with a lot of British folks, who eschew the hyphen in a "double-barreled" last name. For instance, you'd cite:


  Vaughan Williams, Ralph. The Lark Ascending. London: Oxford University Press (2005). 


and not 


  Williams, Ralph V. The Lark Ascending. London: Oxford University Press (2005). 


In such cases, you just need to look up exactly how the author writes his or her name, and follow that trend. Google Scholar can be a good source of such information; Web of Science and other citation-tracking sites are often better.

The most useful method of all would be to find "self-citations": works where the author cites his or her own work. How the name is written under those circumstances should be the most unambiguous statement.