Since you're submitting a paper to a journal that has certain formatting requirements for the paper's bibliography (and lots of other aspects of the paper too, no doubt!), you should ask (if you haven't already done so) for a BibTeX bibliography style (.bst) file that implements the journal's requirements. With any luck, this .bst file will be compatible with natbib and also implement the journal's house style (of making you cite the names of all authors of pieces that have three or fewer authors).
If you're not that lucky, there are three possibilities. First, if the .bst file is not compatible with natbib, you're obviously out of luck. (Fortunately, though, natbib is enormously robust and works with the overwhelming majority of .bst files.) Second, if the .bst file is compatible with natbib but does not contain a function called format.lab.names, you're also out of luck. That's what's meant, basically, by the statement in natbib's manual that "starred [citation command] versions can only list the full authors if the .bst file supports this feature." (Of course, such a .bst file must also provide a few functions that call the format.lab.names function...)
Third, if the .bst file does contain such a function but doesn't implement the journal's house style, i.e., if the \cite[pt]* macros output Adams et~al. for a piece that has exactly three authors (and the first author's surname is "Adams"...), you are not out of luck. All you need to do is to replace the existing format.lab.names function with one that does obey the journal's house style. The existing format.lab.names function should (more or less...) look like:
FUNCTION {format.lab.names}
{ 's :=
"" 't :=
s #1 "{vv~}{ll}" format.name$
s num.names$ duplicate$
#2 >
{ pop$
" " * bbl.etal *
}
{ #2 <
'skip$
{ s #2 "{ff }{vv }{ll}{ jj}" format.name$ "others" =
{
" " * bbl.etal *
}
{ bbl.and space.word * s #2 "{vv~}{ll}" format.name$
* }
if$
}
if$
}
if$
}
You should replace this code with the following code:
FUNCTION {format.lab.names}
{'s :=
"" 't :=
#1 'nameptr :=
s num.names$ 'numnames :=
numnames 'namesleft :=
{ namesleft #0 > }
{ s nameptr
"{vv~}{ll}" format.name$
't :=
nameptr #1 >
{
nameptr #2 =
numnames #3 > and
{ "others" 't :=
#1 'namesleft := }
'skip$
if$
namesleft #1 >
{ ", " * t * }
{
s nameptr "{ll}" format.name$ duplicate$ "others" =
{ 't := }
{ pop$ }
if$
t "others" =
{
" " * bbl.etal *
}
{
numnames #2 >
{ "," * }
'skip$
if$
bbl.and
space.word * t *
}
if$
}
if$
}
't
if$
nameptr #1 + 'nameptr :=
namesleft #1 - 'namesleft :=
}
while$
}
After making this replacement, save the .bst file under a new name and adjust the \bibliographystyle command to point to the new file.
If you get complaints from BibTeX about nonexistent bbl.and and/or bbl.etal functions, just add the following code to the new .bst file (somewhere near the top of the file, soon after the start of the section in which the bibtex functions are defined):
FUNCTION {bbl.and}
{ "and"}
FUNCTION {bbl.etal}
{ "et~al." }
natbibmanual states that the "starred [citation command] versions can only list the full authors if the .bst file supports this feature; otherwise, the abbreviated list is printed." – Mico Dec 15 '11 at 20:32But I'm pretty sure that this isn't really relevant. I'm not trying to use the starred citation format. The starred citation format works fine with this version of bst, but does not do what I want.
What I want is something that will automatically identify citations with three authors, and expand those without messing with longer citation lists.
– Alex T. Dec 16 '11 at 16:05\citetand\citepcommands. The\citetand\citepcommands will list all authors if there are fewer than four of them, and they'll generate a "FirstAuthor et al" citation in all other cases. – Mico Dec 16 '11 at 16:21