There is a tool to generate custom bib-styles, makebst.tex. When I run it as
latex /usr/share/texmf-texlive/tex/latex/custom-bib/makebst.tex
it asks a lot of questions, and in particular, it allows to select capitalization of article titles:
CAPITALIZATION OF ARTICLE TITLE:
(*) Sentence style (capitalize first word and those in braces)
(t) Title style (just as in bib entry)
Select:
\ans=t
You have selected: Title style
There is no such option for book titles though... But even in this case “Title” style means only “just as in bib entry”. So probably you need to capitalize titles manually.
