diff -r f26dc3004b3f -r 0dcd4f8c2b8a plugins/redmine_bibliography/Gemfile
--- a/plugins/redmine_bibliography/Gemfile
+++ b/plugins/redmine_bibliography/Gemfile
@@ -1,5 +1,6 @@
 gem 'bibtex-ruby'
 gem 'nokogiri'
+gem 'csl'
+gem 'csl-styles'
 gem 'citeproc'
 gem 'citeproc-ruby'
-gem 'csl-styles'