Because of the warning message
Warning--I'm ignoring cwang10's extra "title" field
combined with the fact that you have "about 120" reference entries, I'm almost positive that you've run into BibTeX capacity issues. Quoting sections 2.4.2.1 and 2.4.2.2 of the biblatex (sic!) manual:
With a large bib file which contains several hundred entries, BibTeX
is very likely to run out of memory. [...] Unfortunately, traditional
BibTeX does not output a clear error message when it runs out of
memory but exposes a rather cryptical kind of faulty behavior. The
warning messages printed in this case look like this:
Warning--I’m ignoring Jones1995’s extra "year" field
--line 422 of file huge.bib
[...]
These warning messages could indeed indicate that the entry
Jones1995 is faulty because it includes two year [...]
fields. If that is not the case and the bib file is fairly large,
this is most likely a capacity issue. What makes these warnings so
confusing is that they are not tied to a specific entry. If you remove
the allegedly faulty entry, a different one will trigger similar
warnings. This is one reason why switching to bibtex8 [...] is
advisable.
[...]
[T]he capacity of [bibtex8] may be increased at run-time via
command-line switches and it also prints unambiguous error messages,
for example:
17289 fields:
Sorry---you’ve exceeded BibTeX’s total number of fields 17250
[...] The first thing you should always do is run bibtex8 with the
--wolfgang switch. Don’t even bother trying anything else.
In other words, try to compile your document using
pdflatex
bibtex8 --wolfgang
pdflatex
pdflatex
bibtex8instead ofbibtex; i.e., process your document using(pdf)latex + bibtex8 + (pdf)latex + (pdf)latex. – Gonzalo Medina May 18 '12 at 3:58