diff --git a/.travis.yml b/.travis.yml
index 3344c9f..7817ee8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,8 +4,10 @@ cache: bundler
 
 matrix:
   include:
-  - rvm: 2.7
+  - rvm: 3.0
     env: WITH_COVERALLS=true
+  - rvm: 2.7
+    env: WITH_COVERALLS=false
   - rvm: 2.6
     env: WITH_COVERALLS=false
   - rvm: 2.5
diff --git a/Gemfile.lock b/Gemfile.lock
index 0406e7a..ef1fb3a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,8 +1,9 @@
 PATH
   remote: .
   specs:
-    bibtex-ruby (5.1.4)
+    bibtex-ruby (5.1.6)
       latex-decode (~> 0.0)
+      rexml (~> 3.0)
 
 GEM
   remote: https://rubygems.org/
@@ -87,6 +88,7 @@ GEM
     redcarpet (3.5.0)
     rest-client (1.6.7)
       mime-types (>= 1.16)
+    rexml (3.2.4)
     ruby-prof (1.4.1)
     simplecov (0.19.0)
       docile (~> 1.1)
diff --git a/bibtex-ruby.gemspec b/bibtex-ruby.gemspec
index a994d77..3e8d637 100644
--- a/bibtex-ruby.gemspec
+++ b/bibtex-ruby.gemspec
@@ -26,6 +26,7 @@ Gem::Specification.new do |s|
   END_DESCRIPTION
 
   s.add_runtime_dependency('latex-decode', ['~>0.0'])
+  s.add_runtime_dependency('rexml', ['~>3.0'])
 
   s.files        = File.open('Manifest').readlines.map(&:chomp)
   s.test_files   = Dir.glob('test/**/test*.rb')