diff --git a/.gitignore b/.gitignore
index 45732eed1..6c0e58a8b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,7 @@ _site
 .sass-cache
 .jekyll-metadata
 .tweet-cache
+.jekyll-cache
 
 # Unix
 *~
diff --git a/Gemfile b/Gemfile
index 5938ee89e..ca322e984 100644
--- a/Gemfile
+++ b/Gemfile
@@ -22,3 +22,4 @@ gem "less"
 gem "therubyracer"
 gem "json"
 gem "unicode"
+gem "citeproc-ruby", ">= 1.1.12"
diff --git a/Gemfile.lock b/Gemfile.lock
index ed498e724..78d8935fa 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,29 +1,29 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.2)
-      public_suffix (>= 2.0.2, < 4.0)
-    bibtex-ruby (4.4.7)
+    addressable (2.7.0)
+      public_suffix (>= 2.0.2, < 5.0)
+    bibtex-ruby (5.1.4)
       latex-decode (~> 0.0)
-    citeproc (1.0.9)
+    citeproc (1.0.10)
       namae (~> 1.0)
-    citeproc-ruby (1.1.10)
+    citeproc-ruby (1.1.12)
       citeproc (~> 1.0, >= 1.0.9)
       csl (~> 1.5)
     colorator (1.1.0)
     colored (1.2)
     commonjs (0.2.7)
-    concurrent-ruby (1.0.5)
-    csl (1.5.0)
+    concurrent-ruby (1.1.6)
+    csl (1.5.1)
       namae (~> 1.0)
-    csl-styles (1.0.1.8)
+    csl-styles (1.0.1.10)
       csl (~> 1.0)
     diff-lcs (1.3)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
     eventmachine (1.2.7)
-    ffi (1.9.25)
+    ffi (1.12.2)
     forwardable-extended (2.6.0)
     git-up (0.5.12)
       colored (>= 1.2)
@@ -33,73 +33,78 @@ GEM
       mime-types (~> 1.15)
       posix-spawn (~> 0.3.6)
     http_parser.rb (0.6.0)
-    i18n (0.9.5)
+    i18n (1.8.2)
       concurrent-ruby (~> 1.0)
-    jekyll (3.8.3)
+    jekyll (4.0.1)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
-      i18n (~> 0.7)
-      jekyll-sass-converter (~> 1.0)
+      i18n (>= 0.9.5, < 2)
+      jekyll-sass-converter (~> 2.0)
       jekyll-watch (~> 2.0)
-      kramdown (~> 1.14)
+      kramdown (~> 2.1)
+      kramdown-parser-gfm (~> 1.0)
       liquid (~> 4.0)
       mercenary (~> 0.3.3)
       pathutil (~> 0.9)
-      rouge (>= 1.7, < 4)
+      rouge (~> 3.0)
       safe_yaml (~> 1.0)
-    jekyll-last-modified-at (1.0.1)
-      jekyll (~> 3.3)
+      terminal-table (~> 1.8)
+    jekyll-last-modified-at (1.3.0)
+      jekyll (>= 3.7, < 5.0)
       posix-spawn (~> 0.3.9)
-    jekyll-sass-converter (1.5.2)
-      sass (~> 3.4)
-    jekyll-scholar (5.14.0)
-      bibtex-ruby (~> 4.0, >= 4.0.13)
+    jekyll-sass-converter (2.1.0)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-scholar (6.7.0)
+      bibtex-ruby (~> 5.0)
       citeproc-ruby (~> 1.0)
       csl-styles (~> 1.0)
-      jekyll (~> 3.0)
-    jekyll-twitter-plugin (2.0.0)
-    jekyll-watch (2.1.2)
+      jekyll (~> 4.0)
+    jekyll-twitter-plugin (2.1.0)
+    jekyll-watch (2.2.1)
       listen (~> 3.0)
-    json (2.1.0)
-    kramdown (1.17.0)
+    json (2.3.0)
+    kramdown (2.2.1)
+      rexml
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
     latex-decode (0.3.1)
     less (2.6.0)
       commonjs (~> 0.2.7)
     libv8 (3.16.14.19)
-    liquid (4.0.1)
-    listen (3.1.5)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-      ruby_dep (~> 1.2)
+    liquid (4.0.3)
+    listen (3.2.1)
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
     mime-types (1.25.1)
     namae (1.0.1)
-    pathutil (0.16.1)
+    pathutil (0.16.2)
       forwardable-extended (~> 2.6)
-    posix-spawn (0.3.13)
-    public_suffix (3.0.2)
-    rb-fsevent (0.10.3)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
+    posix-spawn (0.3.14)
+    public_suffix (4.0.5)
+    rb-fsevent (0.10.4)
+    rb-inotify (0.10.1)
+      ffi (~> 1.0)
     ref (2.0.0)
-    rouge (3.1.1)
-    ruby_dep (1.5.0)
-    safe_yaml (1.0.4)
-    sass (3.5.7)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
+    rexml (3.2.4)
+    rouge (3.19.0)
+    safe_yaml (1.0.5)
+    sassc (2.3.0)
+      ffi (~> 1.9)
+    terminal-table (1.8.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
     therubyracer (0.12.3)
       libv8 (~> 3.16.14.15)
       ref
     unicode (0.4.4.4)
+    unicode-display_width (1.7.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
+  citeproc-ruby (>= 1.1.12)
   ffi (>= 1.9.24)
   git-up
   jekyll (>= 3.6.3)
@@ -112,7 +117,7 @@ DEPENDENCIES
   unicode
 
 RUBY VERSION
-   ruby 2.3.1p112
+   ruby 2.7.0p0
 
 BUNDLED WITH
-   2.0.2
+   2.1.4
diff --git a/Makefile b/Makefile
index 0834b2738..ccf376d42 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ MARIAN   = marian/build
 COMMANDS = marian marian-decoder marian-server marian-scorer marian-vocab marian-conv
 CMDFILES = $(patsubst %,docs/cmd/%.md,$(COMMANDS))
 
-.PHONY: build clean update-cmds update-docs install run zip Gamefile.lock
+.PHONY: build clean update-gems update-cmds update-docs install run zip Gamefile.lock
 
 
 all: run
@@ -16,9 +16,9 @@ run: build
 build:
 	bundle exec jekyll build
 
-install: Gemfile.lock
+install: Gemfile
 	bundle install
-Gemfile.lock: Gemfile
+update-gems: Gemfile
 	bundle update