CiteProc

$ [sudo] gem install citeproc-ruby
$ [sudo] gem install csl-styles

require 'citeproc'
require 'csl/styles'
require 'bibtex'

# Create a new processor
# with the desired style, format, and locale.
cp = CiteProc::Processor.new style: 'apa', format: 'text'

# To see what styles are available in your current environment,
# run `CSL::Style.ls';
# this also works for locales as `CSL::Locale.ls'.

# Tell the processor where to find your references.
# In this example we load them from a BibTeX bibliography
# using the bibtex-ruby gem (`gem install bibtex-ruby').
cp.import BibTeX.open('./references.bib').to_citeproc

# Now you are ready for rendering;
# the processor API provides two main rendering methods:
# `process' and `bibliography'.

# For simple one-off renditions,
# you can also call `render' in bibliography or citation mode:
cp.render :bibliography, id: 'knuth'

# This will return a rendered reference, like:
#-> Knuth, D. (1968). The art of computer programming (Vol. 1). Addison-Wesley.

# CiteProc-Ruby exposes a full CSL API to you;
# this makes it possible to just alter CSL styles on the fly.
# For example, what if we want names not to be initialized
# even though APA style is configured to do so?
# We could change the CSL style itself,
# but we can also make a quick adjustment at runtime:
cp.engine.style.macros['author-bib'].each_descendant do |node|
  node[:initialize] = 'false' if node.nodename == 'name'
end

# What just happened?
# We selected the current style's 'author-bib' macro
# and changed all of its CSL name nodes;
# the cite processor output will pick-up the changes right away:

cp.render :bibliography, id: 'knuth'
#-> Knuth, Donald. (1968). The art of computer programming (Vol. 1). Addison-Wesley.

# Note that we have picked 'text' as the output format;
# if we want to make use of richer output formats
# we can switch to HTML instead:
cp.engine.format = 'html'

cp.render :bibliography, id: 'knuth'
#-> Knuth, Donald. (1968). <i>The art of computer programming</i> (Vol. 1). Addison-Wesley.

# You can also render citations on the fly.
cp.render :citation, id: 'knuth', locator: '23', label: 'page'
#-> (Knuth, 1968, p. 23)

/usr/local/share/csl/styles
/usr/local/share/csl/locales

$ bundle install
$ bundle exec rake

$ bundle exec cucumber