diff --git a/.rubocop.yml b/.rubocop.yml
index c7c5fae..f34db8d 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -5,7 +5,7 @@ require:
   - rubocop-rake
 
 AllCops:
-  TargetRubyVersion: 3.3
+  TargetRubyVersion: 3.2
   DisplayCopNames: true
   NewCops: enable
 
@@ -21,9 +21,6 @@ Lint/AmbiguousOperatorPrecedence:
 Lint/ReturnInVoidContext:
   Enabled: false
 
-Metrics/ClassLength:
-  Max: 200
-
 Style/AndOr:
   EnforcedStyle: conditionals
 
@@ -36,9 +33,6 @@ Style/HashAsLastArrayItem:
 Style/PerlBackrefs:
   Enabled: false
 
-Style/SuperWithArgsParentheses:
-  Enabled: false
-
 Style/TrailingCommaInArguments:
   EnforcedStyleForMultiline: comma
 
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 986620e..47477d5 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2024-10-18 19:44:25 UTC using RuboCop version 1.67.0.
+# on 2024-10-18 14:41:13 UTC using RuboCop version 1.67.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -22,10 +22,23 @@ Layout/LineLength:
   Exclude:
     - 'lib/repubmark/elems/footnote.rb'
 
-# Offense count: 2
+# Offense count: 1
+# This cop supports safe autocorrection (--autocorrect).
+# Configuration parameters: AllowedMethods.
+# AllowedMethods: present?, blank?, presence, try, try!, in?
+Lint/SafeNavigationChain:
+  Exclude:
+    - 'lib/repubmark/elems/article.rb'
+
+# Offense count: 1
 # Configuration parameters: AllowedMethods, AllowedPatterns, CountRepeatedAttributes.
 Metrics/AbcSize:
-  Max: 36
+  Max: 35
+
+# Offense count: 1
+# Configuration parameters: CountComments, CountAsOne.
+Metrics/ClassLength:
+  Max: 104
 
 # Offense count: 1
 # Configuration parameters: AllowedMethods, AllowedPatterns.
@@ -35,14 +48,32 @@ Metrics/CyclomaticComplexity:
 # Offense count: 5
 # Configuration parameters: CountComments, CountAsOne, AllowedMethods, AllowedPatterns.
 Metrics/MethodLength:
-  Max: 31
+  Max: 33
 
 # Offense count: 1
 # Configuration parameters: AllowedMethods, AllowedPatterns.
 Metrics/PerceivedComplexity:
   Max: 11
 
-# Offense count: 36
+# Offense count: 2
+Performance/MapMethodChain:
+  Exclude:
+    - 'lib/repubmark/elems/footnotes_category.rb'
+
+# Offense count: 14
+# This cop supports safe autocorrection (--autocorrect).
+# Configuration parameters: AllowOnlyRestArgument, UseAnonymousForwarding, RedundantRestArgumentNames, RedundantKeywordRestArgumentNames, RedundantBlockArgumentNames.
+# RedundantRestArgumentNames: args, arguments
+# RedundantKeywordRestArgumentNames: kwargs, options, opts
+# RedundantBlockArgumentNames: blk, block, proc
+Style/ArgumentsForwarding:
+  Exclude:
+    - 'lib/repubmark/elems/canvas.rb'
+    - 'lib/repubmark/elems/footnotes_category.rb'
+    - 'lib/repubmark/elems/joint.rb'
+    - 'lib/repubmark/elems/link.rb'
+
+# Offense count: 34
 # Configuration parameters: AllowedConstants.
 Style/Documentation:
   Enabled: false
@@ -66,3 +97,33 @@ Style/RedundantFreeze:
   Exclude:
     - 'lib/repubmark/elems/fraction.rb'
     - 'lib/repubmark/elems/power.rb'
+
+# Offense count: 2
+# This cop supports safe autocorrection (--autocorrect).
+Style/RedundantStringEscape:
+  Exclude:
+    - 'lib/repubmark/elems/footnote.rb'
+
+# Offense count: 1
+# This cop supports safe autocorrection (--autocorrect).
+# Configuration parameters: AllowModifier.
+Style/SoleNestedConditional:
+  Exclude:
+    - 'lib/repubmark/elems/footnote.rb'
+
+# Offense count: 7
+# This cop supports safe autocorrection (--autocorrect).
+Style/SuperArguments:
+  Exclude:
+    - 'lib/repubmark/elems/annotation.rb'
+    - 'lib/repubmark/elems/blockquote.rb'
+    - 'lib/repubmark/elems/canvas.rb'
+    - 'lib/repubmark/elems/caption.rb'
+    - 'lib/repubmark/elems/figures.rb'
+    - 'lib/repubmark/elems/joint.rb'
+    - 'lib/repubmark/elems/paragraph.rb'
+
+# Offense count: 24
+# This cop supports safe autocorrection (--autocorrect).
+Style/SuperWithArgsParentheses:
+  Enabled: false
diff --git a/Gemfile b/Gemfile
index c787375..d3b131c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ source 'https://rubygems.org'
 gemspec
 
 group :development do
-  gem 'bundler',             '~> 2.5'
+  gem 'bundler',             '~> 2.4'
   gem 'pry',                 '~> 0.14'
   gem 'rake',                '~> 13.2'
   gem 'rubocop',             '~> 1.67'
diff --git a/Rakefile b/Rakefile
index 628f9d2..1b2cd40 100644
--- a/Rakefile
+++ b/Rakefile
@@ -27,8 +27,8 @@ task test: :tests
 desc 'Run code analysis tools'
 task lint: %i[rubocop yard:cov]
 
-desc 'Fix code style (rubocop --autocorrect)'
-task fix: 'rubocop:autocorrect'
+desc 'Fix code style (rubocop --auto-correct)'
+task fix: 'rubocop:auto_correct'
 
 Rake::Task['release'].prereqs.unshift 'default'
 Rake::Task['release:rubygem_push'].clear
@@ -68,6 +68,6 @@ namespace :yard do
 
     coverage = m[1].to_f.round(2)
     puts "Documentation coverage: #{coverage}%"
-    raise 'Not fully documented!' if coverage < 36
+    raise 'Not fully documented!' if coverage < 38
   end
 end
diff --git a/lib/repubmark.rb b/lib/repubmark.rb
index e91fdcf..a244dd4 100644
--- a/lib/repubmark.rb
+++ b/lib/repubmark.rb
@@ -16,9 +16,6 @@ require_relative 'repubmark/titled_ref'
 require_relative 'repubmark/config'
 require_relative 'repubmark/config/css_classes'
 
-require_relative 'repubmark/references/author'
-require_relative 'repubmark/references/item'
-
 require_relative 'repubmark/elems/base'
 
 # Top-level element
@@ -75,10 +72,7 @@ require_relative 'repubmark/elems/footnote'
 module Repubmark
   FORMATS = %i[chapters gemtext html summary_plain word_count].freeze
 
-  SLUG_RE      = /\A[[:word:]]+(-[[:word:]]+)*\z/
-  DOI_RE       = %r{\A10(\.\d+)+/\w+(\.\w+)*\z}
-  ISBN_RE      = /\A[0-9]{13}\z/
-  NAME_PART_RE = /\A[[:word:]]+(-[[:word:]]+)*( [[:word:]]+(-[[:word:]]+)*)*\z/
+  SLUG_RE = /\A[[:word:]]+(-[[:word:]]+)*\z/
 
   UNICODE_SUPS = {
     '0' => '⁰',
@@ -123,46 +117,6 @@ module Repubmark
     slug
   end
 
-  def self.validate_doi!(doi)
-    doi = String(doi).freeze
-    raise 'Invalid DOI' unless DOI_RE.match? doi
-
-    doi
-  end
-
-  def self.validate_isbn!(isbn)
-    isbn = String(isbn).freeze
-    raise 'Invalid ISBN' unless ISBN_RE.match? isbn
-
-    isbn
-  end
-
-  def self.validate_name_part!(name_part)
-    name_part = String(name_part).freeze
-    raise 'Invalid name part' unless NAME_PART_RE.match? name_part
-
-    name_part
-  end
-
-  def self.validate_text!(str)
-    str = String(str).freeze
-    raise 'Invalid text' if str.empty? || str != str.strip
-
-    str
-  end
-
-  def self.validate_absolute_url!(url)
-    url = Addressable::URI.parse(url).freeze
-    raise 'Invalid URL' unless url.absolute? &&
-                               url.scheme &&
-                               !url.scheme.strip.empty? &&
-                               url.host &&
-                               !url.host.strip.empty? &&
-                               url.userinfo.nil?
-
-    url
-  end
-
   def self.unicode_sup(val)
     String(val).each_char.map { |chr| UNICODE_SUPS.fetch chr }.join.freeze
   end
diff --git a/lib/repubmark/elems/annotation.rb b/lib/repubmark/elems/annotation.rb
index dd43ee8..74f0b3f 100644
--- a/lib/repubmark/elems/annotation.rb
+++ b/lib/repubmark/elems/annotation.rb
@@ -6,7 +6,7 @@ module Repubmark
       parents :Article
 
       def initialize(parent)
-        super
+        super parent
         @canvas = Canvas.new self
       end
 
diff --git a/lib/repubmark/elems/article.rb b/lib/repubmark/elems/article.rb
index adc0e21..bec8aa3 100644
--- a/lib/repubmark/elems/article.rb
+++ b/lib/repubmark/elems/article.rb
@@ -45,7 +45,7 @@ module Repubmark
         ].compact.join("\n\n\n").freeze
       end
 
-      def chapters = (@chapter&.chapters || {})[:chapters] || [].freeze
+      def chapters = @chapter&.chapters[:chapters] || [].freeze
 
       ###################
       # Builder methods #
diff --git a/lib/repubmark/elems/blockquote.rb b/lib/repubmark/elems/blockquote.rb
index bc36789..c019e50 100644
--- a/lib/repubmark/elems/blockquote.rb
+++ b/lib/repubmark/elems/blockquote.rb
@@ -6,7 +6,7 @@ module Repubmark
       parents :Canvas
 
       def initialize(parent)
-        super
+        super parent
 
         @canvas = Canvas.new self
         @caption = nil
diff --git a/lib/repubmark/elems/canvas.rb b/lib/repubmark/elems/canvas.rb
index 9af10aa..43762e8 100644
--- a/lib/repubmark/elems/canvas.rb
+++ b/lib/repubmark/elems/canvas.rb
@@ -6,7 +6,7 @@ module Repubmark
       parents :Annotation, :Blockquote, :Chapter
 
       def initialize(parent)
-        super
+        super parent
         @items = []
       end
 
@@ -41,14 +41,14 @@ module Repubmark
         nil
       end
 
-      def code_block(*, **)
-        code_block = CodeBlock.new(self, *, **)
+      def code_block(*args, **kwargs)
+        code_block = CodeBlock.new self, *args, **kwargs
         @items << code_block
         nil
       end
 
-      def iframe(*, **)
-        iframe = Iframe.new(self, *, **)
+      def iframe(*args, **kwargs)
+        iframe = Iframe.new self, *args, **kwargs
         @items << iframe
         nil
       end
diff --git a/lib/repubmark/elems/caption.rb b/lib/repubmark/elems/caption.rb
index 96eff05..b3b5264 100644
--- a/lib/repubmark/elems/caption.rb
+++ b/lib/repubmark/elems/caption.rb
@@ -8,7 +8,7 @@ module Repubmark
       parents :Blockquote, :Figure, :Footnote, :ListItem, :Paragraph
 
       def initialize(parent)
-        super
+        super parent
         @items = []
       end
 
diff --git a/lib/repubmark/elems/figures.rb b/lib/repubmark/elems/figures.rb
index 817132a..b109e18 100644
--- a/lib/repubmark/elems/figures.rb
+++ b/lib/repubmark/elems/figures.rb
@@ -6,7 +6,7 @@ module Repubmark
       parents :Canvas
 
       def initialize(parent)
-        super
+        super parent
         @figures = []
       end
 
diff --git a/lib/repubmark/elems/footnote.rb b/lib/repubmark/elems/footnote.rb
index d376ceb..167d1b6 100644
--- a/lib/repubmark/elems/footnote.rb
+++ b/lib/repubmark/elems/footnote.rb
@@ -30,10 +30,12 @@ module Repubmark
         end
         if url
           scheme = Addressable::URI.parse(url).scheme&.downcase
-          if scheme && !%w[http https].include?(scheme)
-            result += %(<span class="badge text-bg-secondary">\n)
-            result += %(#{scheme}://\n)
-            result += "</span>\n"
+          if scheme
+            unless %w[http https].include? scheme
+              result += %(<span class="badge text-bg-secondary">\n)
+              result += %(#{scheme}://\n)
+              result += "</span>\n"
+            end
           end
           result += %(<a href="#{url}">#{link_text}</a>\n)
         else
@@ -43,7 +45,7 @@ module Repubmark
         if alt_urls&.any?
           result += %[(#{
             alt_urls.map do |alt_url|
-              %(<a href="#{alt_url[:url]}">#{alt_url[:name]}</a>)
+              %(<a href=\"#{alt_url[:url]}\">#{alt_url[:name]}</a>)
             end.join ', '
           })\n]
         end
diff --git a/lib/repubmark/elems/footnotes_category.rb b/lib/repubmark/elems/footnotes_category.rb
index 6a3a320..cc1985c 100644
--- a/lib/repubmark/elems/footnotes_category.rb
+++ b/lib/repubmark/elems/footnotes_category.rb
@@ -20,7 +20,7 @@ module Repubmark
           <h2>#@title</h2>
 
           <ol>
-          #{@footnotes.map { |footnote| footnote.to_html.strip }.join("\n")}
+          #{@footnotes.map(&:to_html).map(&:strip).join("\n")}
           </ol>
         HTML
       end
@@ -29,7 +29,7 @@ module Repubmark
         <<~GEMTEXT
           ## #@title
 
-          #{@footnotes.map { |footnote| footnote.to_gemtext.strip }.join("\n")}
+          #{@footnotes.map(&:to_gemtext).map(&:strip).join("\n")}
         GEMTEXT
       end
 
@@ -37,8 +37,8 @@ module Repubmark
       # Builder methods #
       ###################
 
-      def footnote(**)
-        footnote = Footnote.new(self, **)
+      def footnote(**kwargs)
+        footnote = Footnote.new(self, **kwargs)
         @footnotes << footnote
         yield footnote if block_given?
         nil
diff --git a/lib/repubmark/elems/joint.rb b/lib/repubmark/elems/joint.rb
index 3988f97..b48b463 100644
--- a/lib/repubmark/elems/joint.rb
+++ b/lib/repubmark/elems/joint.rb
@@ -6,7 +6,7 @@ module Repubmark
       parents :Caption, :Quote
 
       def initialize(parent)
-        super
+        super parent
 
         @raw1   = nil
         @base   = nil
@@ -92,7 +92,7 @@ module Repubmark
         base quote
       end
 
-      def section(*) = base Section.new(self, *)
+      def section(*args) = base Section.new self, *args
 
       def text(str) = base Text.new self, str
 
diff --git a/lib/repubmark/elems/link.rb b/lib/repubmark/elems/link.rb
index 6e326f5..df306d2 100644
--- a/lib/repubmark/elems/link.rb
+++ b/lib/repubmark/elems/link.rb
@@ -7,8 +7,8 @@ module Repubmark
 
       SCHEMES = %w[http https].freeze
 
-      def initialize(parent, str, uri, **)
-        super(parent, str, **)
+      def initialize(parent, str, uri, **kwargs)
+        super parent, str, **kwargs
 
         self.uri = uri
         validate_uri!
diff --git a/lib/repubmark/elems/paragraph.rb b/lib/repubmark/elems/paragraph.rb
index 5568362..979e8e4 100644
--- a/lib/repubmark/elems/paragraph.rb
+++ b/lib/repubmark/elems/paragraph.rb
@@ -6,7 +6,7 @@ module Repubmark
       parents :Canvas
 
       def initialize(parent)
-        super
+        super parent
         @caption = Caption.new self
       end
 
diff --git a/lib/repubmark/references/author.rb b/lib/repubmark/references/author.rb
deleted file mode 100644
index 200934d..0000000
--- a/lib/repubmark/references/author.rb
+++ /dev/null
@@ -1,31 +0,0 @@
-# frozen_string_literal: true
-
-module Repubmark
-  module References
-    class Author
-      attr_reader :family, :given
-
-      def initialize(family, given)
-        self.family = family
-        self.given  = given
-      end
-
-      def inspect = "#<#{self.class}: #{self}>".freeze
-
-      def to_s = "#{family}, #{given.join(' ')}".freeze
-
-      alias to_str to_s
-
-    private
-
-      def family=(family)
-        @family = Repubmark.validate_name_part! family
-      end
-
-      def given=(given)
-        @given =
-          Array(given).map { |part| Repubmark.validate_name_part! part }.freeze
-      end
-    end
-  end
-end
diff --git a/lib/repubmark/references/item.rb b/lib/repubmark/references/item.rb
deleted file mode 100644
index 851a613..0000000
--- a/lib/repubmark/references/item.rb
+++ /dev/null
@@ -1,52 +0,0 @@
-# frozen_string_literal: true
-
-module Repubmark
-  module References
-    class Item
-      ATTRIBUTES = %i[slug doi isbn title urls authors].freeze
-      attr_reader(*ATTRIBUTES)
-
-      def initialize(**kwargs)
-        ATTRIBUTES.each { |attr| send :"#{attr}=", kwargs[attr] }
-      end
-
-      def inspect = "#<#{self.class}:#{slug}>".freeze
-
-    private
-
-      def slug=(slug)
-        @slug = Repubmark.validate_slug! slug
-      end
-
-      def doi=(doi)
-        @doi = Repubmark.validate_doi! doi if doi
-      end
-
-      def isbn=(isbn)
-        @isbn = Repubmark.validate_isbn! isbn if isbn
-      end
-
-      def title=(title)
-        @title = Repubmark.validate_text! title
-      end
-
-      def urls=(urls)
-        urls = Array urls
-        return @urls = [].freeze if urls.empty?
-
-        @urls = urls.map { |url| Repubmark.validate_absolute_url! url }.freeze
-      end
-
-      def authors=(authors)
-        authors = Array authors
-        return @authors = [].freeze if authors.empty?
-
-        @authors = authors.freeze.each do |author|
-          unless author.instance_of? Author
-            raise TypeError, "Expected #{Author}, got #{author.class}"
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/repubmark.gemspec b/repubmark.gemspec
index ee763a7..da87d41 100644
--- a/repubmark.gemspec
+++ b/repubmark.gemspec
@@ -14,7 +14,7 @@ Gem::Specification.new do |spec|
   spec.license  = 'MIT'
   spec.homepage = home
 
-  spec.required_ruby_version = '~> 3.3'
+  spec.required_ruby_version = '~> 3.2'
 
   spec.authors = ['Alex Kotov']
   spec.email   = [mail]