diff --git a/Gemfile.lock b/Gemfile.lock
deleted file mode 100644
index 01a5199..0000000
--- a/Gemfile.lock
+++ /dev/null
@@ -1,67 +0,0 @@
-PATH
-  remote: .
-  specs:
-    relaton-bib (0.4.1)
-      addressable
-      nokogiri
-
-GEM
-  remote: https://rubygems.org/
-  specs:
-    addressable (2.7.0)
-      public_suffix (>= 2.0.2, < 5.0)
-    byebug (11.0.1)
-    debase (0.2.3)
-      debase-ruby_core_source (>= 0.10.2)
-    debase-ruby_core_source (0.10.5)
-    diff-lcs (1.3)
-    docile (1.3.2)
-    equivalent-xml (0.6.0)
-      nokogiri (>= 1.4.3)
-    json (2.2.0)
-    mini_portile2 (2.4.0)
-    nokogiri (1.10.3)
-      mini_portile2 (~> 2.4.0)
-    optout (0.0.2)
-    public_suffix (4.0.1)
-    rake (10.5.0)
-    rspec (3.8.0)
-      rspec-core (~> 3.8.0)
-      rspec-expectations (~> 3.8.0)
-      rspec-mocks (~> 3.8.0)
-    rspec-core (3.8.2)
-      rspec-support (~> 3.8.0)
-    rspec-expectations (3.8.4)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-mocks (3.8.1)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-support (3.8.2)
-    ruby-debug-ide (0.7.0)
-      rake (>= 0.8.1)
-    ruby-jing (0.0.1)
-      optout (>= 0.0.2)
-    simplecov (0.17.0)
-      docile (~> 1.1)
-      json (>= 1.8, < 3)
-      simplecov-html (~> 0.10.0)
-    simplecov-html (0.10.2)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  bundler (~> 2.0)
-  byebug
-  debase
-  equivalent-xml (~> 0.6)
-  rake (~> 10.0)
-  relaton-bib!
-  rspec (~> 3.0)
-  ruby-debug-ide
-  ruby-jing
-  simplecov
-
-BUNDLED WITH
-   2.0.2
diff --git a/relaton-bib.gemspec b/relaton-bib.gemspec
index 63769f6..324c2f0 100644
--- a/relaton-bib.gemspec
+++ b/relaton-bib.gemspec
@@ -23,7 +23,6 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
   spec.required_ruby_version = Gem::Requirement.new(">= 2.4.0")
 
-  spec.add_development_dependency "bundler"
   spec.add_development_dependency "debase"
   spec.add_development_dependency "equivalent-xml", "~> 0.6"
   spec.add_development_dependency "rake", "~> 10.0"