How to define citation style?

[breaker84]

Unknown citation style 'harvard' for eprint dataset: using default
Unknown citation style 'vancouver' for eprint dataset: using default
Unknown citation style 'apa' for eprint dataset: using default
EPScript error: Script in citation eprint/summary_page: eprint object does not h ave a 'handle' field at character 6
$item.property('handle')
^ here at /usr/share/eprints3/bin/../perl_lib/EPrints/Script.pm line 162.