diff --git a/.gitignore b/.gitignore
index 569684e9a..f6515aee5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,4 @@ spec/fixtures/vcr
 coverage/
 .coveralls.yml
 .idea/
+documentation/
diff --git a/lib/cocoapods-core/lockfile.rb b/lib/cocoapods-core/lockfile.rb
index 1aa843d96..d75ff7342 100644
--- a/lib/cocoapods-core/lockfile.rb
+++ b/lib/cocoapods-core/lockfile.rb
@@ -135,18 +135,21 @@ def dependencies
     #
     # @return [Dependency] the generated dependency.
     #
-    def dependency_to_lock_pod_named(name)
-      dep = dependencies.find { |d| d.name == name || d.root_name == name }
-      version = version(name)
-
-      unless dep && version
+    def dependencies_to_lock_pod_named(name)
+      result = []
+      deps = dependencies.select { |d| d.root_name == name }
+      if deps.empty?
         raise StandardError, "Attempt to lock the `#{name}` Pod without an " \
           'known dependency.'
       end
 
-      locked_dependency = dep.dup
-      locked_dependency.specific_version = version
-      locked_dependency
+      deps.each do |dep|
+        version = version(dep.name)
+        locked_dependency = dep.dup
+        locked_dependency.specific_version = version
+        result << locked_dependency
+      end
+      result
     end
 
     # @return [Version] The version of CocoaPods which generated this lockfile.
@@ -233,8 +236,8 @@ def detect_changes_with_podfile(podfile)
       [:added, :changed, :removed, :unchanged].each { |k| result[k] = [] }
 
       installed_deps = dependencies.map do |dep|
-        dependency_to_lock_pod_named(dep.name)
-      end
+        dependencies_to_lock_pod_named(dep.name)
+      end.flatten
       all_dep_names  = (dependencies + podfile.dependencies).map(&:name).uniq
       all_dep_names.each do |name|
         installed_dep = installed_deps.find { |d| d.name == name }
diff --git a/lib/cocoapods-core/podfile.rb b/lib/cocoapods-core/podfile.rb
index 7e6f4989d..086ec722d 100644
--- a/lib/cocoapods-core/podfile.rb
+++ b/lib/cocoapods-core/podfile.rb
@@ -95,6 +95,12 @@ def dependencies
 
     # @!group Attributes
 
+    # @return [Array<String>] The name of the sources.
+    #
+    def sources
+      get_hash_value('sources') || []
+    end
+
     # @return [String] the path of the workspace if specified by the user.
     #
     def workspace_path
@@ -173,6 +179,7 @@ def post_install!(installer)
     HASH_KEYS = %w(
       target_definitions
       workspace
+      sources
       generate_bridge_support
       set_arc_compatibility_flag
     ).freeze
diff --git a/lib/cocoapods-core/podfile/dsl.rb b/lib/cocoapods-core/podfile/dsl.rb
index 8758a8adf..090f0c3e1 100644
--- a/lib/cocoapods-core/podfile/dsl.rb
+++ b/lib/cocoapods-core/podfile/dsl.rb
@@ -468,6 +468,44 @@ def set_arc_compatibility_flag!
 
       #-----------------------------------------------------------------------#
 
+      # @!group Sources
+      #
+      #   The Podfile retrieves specs from a given list of sources (repos).
+      #
+      #   Sources are __global__ and they are not stored per target definition.
+
+      #-----------------------------------------------------------------------#
+
+      # Specifies the location of specs
+      #
+      # -----
+      #
+      # By default, the github Cocoapods/specs repository is used. Use this
+      # method to specify (an) other(s) source(s). The order of the sources is
+      # relevant. CocoaPods will use the highest version of a Pod of the first
+      # source which includes the Pod (regardless whether other sources have a
+      # higher version).
+      #
+      # @param    [String] source
+      #           The name of a specs repo. Previously specified by user
+      #           via pod repo add command
+      #
+      # @example  Specifying to use first `my_private_repo` and then the
+      #           CocoaPods Master Repo
+      #
+      #           source 'my_private_repo'
+      #           source 'master'
+      #
+      # @return   [void]
+      #
+      def source(source)
+        hash_sources = get_hash_value('sources') || []
+        hash_sources << source
+        set_hash_value('sources', hash_sources.uniq)
+      end
+
+      #-----------------------------------------------------------------------#
+
       # @!group Hooks
       #   The Podfile provides hooks that will be called during the
       #   installation process.
diff --git a/lib/cocoapods-core/source/aggregate.rb b/lib/cocoapods-core/source/aggregate.rb
index b0e78d442..e5ca8d1ed 100644
--- a/lib/cocoapods-core/source/aggregate.rb
+++ b/lib/cocoapods-core/source/aggregate.rb
@@ -3,38 +3,38 @@ class Source
     # The Aggregate manages a directory of sources repositories.
     #
     class Aggregate
-      # @return [Pathname] the directory were the repositories are stored.
+      # @return [Array<Pathname>] The ordered list of source directories.
       #
-      attr_reader :repos_dir
+      attr_reader :directories
 
-      # @param [Pathname] repos_dir @see repos_dir.
+      # @param  [Array<Pathname>] repos_dirs @see directories
       #
-      def initialize(repos_dir)
-        @repos_dir = repos_dir
+      def initialize(repos_dirs)
+        @directories = Array(repos_dirs)
       end
 
-      # @return [Array<Source>] all the sources.
+      # @return [Array<Source>] The ordered list of the sources.
       #
-      def all
-        @sources ||= dirs.map { |repo| Source.new(repo) }.sort_by(&:name)
+      def sources
+        @sources ||= directories.map { |repo| Source.new(repo) }
       end
 
       # @return [Array<String>] the names of all the pods available.
       #
       def all_pods
-        all.map(&:pods).flatten.uniq
+        sources.map(&:pods).flatten.uniq
       end
 
-      # @return [Array<Set>] the sets for all the pods available.
+      # @return [Array<Set>] The sets for all the pods available.
       #
       # @note   Implementation detail: The sources don't cache their values
       #         because they might change in response to an update. Therefore
-      #         this method to prevent slowness caches the values before
+      #         this method to preserve performance caches the values before
       #         processing them.
       #
       def all_sets
         pods_by_source = {}
-        all.each do |source|
+        sources.each do |source|
           pods_by_source[source] = source.pods
         end
         sources = pods_by_source.keys
@@ -47,20 +47,6 @@ def all_sets
         end
       end
 
-      # @return [Array<Pathname>] the directories where the sources are stored.
-      #
-      # @note   If the repos dir doesn't exits this will return an empty array.
-      #
-      # @raise  If the repos dir doesn't exits.
-      #
-      def dirs
-        if repos_dir.exist?
-          repos_dir.children.select(&:directory?)
-        else
-          []
-        end
-      end
-
       # Returns a set configured with the source which contains the highest
       # version in the aggregate.
       #
@@ -73,7 +59,7 @@ def dirs
       def representative_set(name)
         representative_source = nil
         highest_version = nil
-        all.each do |source|
+        sources.each do |source|
           source_versions = source.versions(name)
           if source_versions
             source_version = source_versions.first
@@ -100,9 +86,9 @@ def representative_set(name)
       # @see    Source#search
       #
       def search(dependency)
-        sources = all.select { |s| s.search(dependency) }
-        unless sources.empty?
-          Specification::Set.new(dependency.root_name, sources)
+        found_sources = sources.select { |s| s.search(dependency) }
+        unless found_sources.empty?
+          Specification::Set.new(dependency.root_name, found_sources)
         end
       end
 
@@ -117,7 +103,7 @@ def search(dependency)
       def search_by_name(query, full_text_search = false)
         pods_by_source = {}
         result = []
-        all.each do |s|
+        sources.each do |s|
           source_pods = s.search_by_name(query, full_text_search)
           pods_by_source[s] = source_pods.map(&:name)
         end
diff --git a/spec/fixtures/Podfile b/spec/fixtures/Podfile
index bbd843b59..265ed45b4 100644
--- a/spec/fixtures/Podfile
+++ b/spec/fixtures/Podfile
@@ -1,3 +1,5 @@
+source 'myrepo1'
+source 'myrepo2'
 platform :ios
 pod 'SSZipArchive',      '>= 1'
 pod 'ASIHTTPRequest',    '~> 1.8.0'
diff --git a/spec/fixtures/Podfile.yaml b/spec/fixtures/Podfile.yaml
index bbadedba2..38f8ec492 100644
--- a/spec/fixtures/Podfile.yaml
+++ b/spec/fixtures/Podfile.yaml
@@ -1,8 +1,12 @@
 ---
+sources:
+  - 'myrepo1'
+  - 'myrepo2'
 target_definitions:
   - name: Pods
     link_with_first_target: true
     platform: ios
+
     dependencies:
     - SSZipArchive:
       - '>= 1'
diff --git a/spec/lockfile_spec.rb b/spec/lockfile_spec.rb
index 863556067..bb5e52694 100644
--- a/spec/lockfile_spec.rb
+++ b/spec/lockfile_spec.rb
@@ -143,12 +143,13 @@ def self.specs
       it 'returns the dependency that locks the pod with the given name to the installed version' do
         json_dep = Dependency.new('JSONKit', '1.4')
         json_dep.external_source = { :podspec => 'path/JSONKit.podspec' }
-        @lockfile.dependency_to_lock_pod_named('JSONKit').should == json_dep
+        result = @lockfile.dependencies_to_lock_pod_named('JSONKit')
+        result.should == [json_dep]
       end
 
       it 'raises if there is a request for a locking dependency for a not stored Pod' do
         should.raise StandardError do
-          @lockfile.dependency_to_lock_pod_named('Missing')
+          @lockfile.dependencies_to_lock_pod_named('Missing')
         end.message.should.match /without an known dependency/
       end
 
diff --git a/spec/podfile_spec.rb b/spec/podfile_spec.rb
index 982fba4f3..5ce977d7f 100644
--- a/spec/podfile_spec.rb
+++ b/spec/podfile_spec.rb
@@ -117,6 +117,21 @@ module Pod
         Podfile.new { set_arc_compatibility_flag! }.should.set_arc_compatibility_flag
       end
 
+      describe 'source' do
+        it 'can have multiple sources' do
+          Podfile.new do
+            source 'new_repo_1'
+            source 'new_repo_2'
+          end.sources.size.should  == 2
+
+          Podfile.new do
+            source 'new_repo_1'
+            source 'new_repo_2'
+            source 'master'
+          end.sources.size.should  == 3
+        end
+
+      end
     end
 
     #-------------------------------------------------------------------------#
@@ -234,6 +249,22 @@ module Pod
         }
       end
 
+      it 'includes the specified sources in the hash representation' do
+        podfile = Podfile.new do
+          source 'new_ASIHTTPRequest_source'
+          pod 'ASIHTTPRequest'
+        end
+        podfile.to_hash.should == {
+          'sources' => %w(new_ASIHTTPRequest_source),
+          'target_definitions' => [
+            {
+              'name' => 'Pods',
+              'link_with_first_target' => true,
+              'dependencies' => %w(ASIHTTPRequest),
+            },
+          ],
+        }
+      end
     end
 
     #-------------------------------------------------------------------------#
diff --git a/spec/source/aggregate_spec.rb b/spec/source/aggregate_spec.rb
index 7ff6f6968..619ef953d 100644
--- a/spec/source/aggregate_spec.rb
+++ b/spec/source/aggregate_spec.rb
@@ -7,15 +7,16 @@ module Pod
     # JSONKit is in test repo has version 1.4 (duplicated) and the 999.999.999.
     #
     before do
-      @subject = Source::Aggregate.new(fixture('spec-repos'))
+      repos = [fixture('spec-repos/test_repo'), fixture('spec-repos/master')]
+      @subject = Source::Aggregate.new(repos)
     end
 
     #-------------------------------------------------------------------------#
 
     describe 'In general' do
 
-      it 'returns all the sources' do
-        @subject.all.map(&:name).should == %w(master test_repo)
+      it 'returns the sources' do
+        @subject.sources.map(&:name).sort.should == %w(master test_repo)
       end
 
       it 'returns the name of all the available pods' do
@@ -55,15 +56,6 @@ module Pod
         set.should.nil?
       end
 
-      it 'returns the directories where the repos are defined' do
-        @subject.dirs.map { |d| d.basename.to_s }.sort.should == %w(master test_repo)
-      end
-
-      it "returns an empty list for the directories if the repos dir doesn't exists" do
-        aggregate = Source::Aggregate.new(Pathname.new('missing-dir'))
-        aggregate.dirs.should == []
-      end
-
       it 'returns a set configured to use only the source which contains the highest version' do
         set = @subject.representative_set('JSONKit')
         set.versions.map(&:to_s).should == ['999.999.999', '1.13', '1.4']
@@ -92,14 +84,14 @@ module Pod
       end
 
       it 'performs a full text search' do
-        @subject.stubs(:dirs).returns([fixture('spec-repos/test_repo')])
+        @subject.stubs(:directories).returns([fixture('spec-repos/test_repo')])
         sets = @subject.search_by_name('Banana Corp', true)
         sets.count.should == 1
         sets.first.name.should == 'BananaLib'
       end
 
       it 'raises an informative if unable to find a Pod with the given name' do
-        @subject.stubs(:dirs).returns([fixture('spec-repos/test_repo')])
+        @subject.stubs(:directories).returns([fixture('spec-repos/test_repo')])
         should.raise Informative do
           @subject.search_by_name('Some-funky-name', true)
         end.message.should.match /Unable to find/
@@ -113,7 +105,7 @@ module Pod
 
       before do
         test_source = Source.new(fixture('spec-repos/test_repo'))
-        @subject.stubs(:all).returns([test_source])
+        @subject.stubs(:sources).returns([test_source])
       end
 
       it 'generates the search index from scratch' do
diff --git a/spec/specification/set/presenter_spec.rb b/spec/specification/set/presenter_spec.rb
index a4de82d98..7e0962699 100644
--- a/spec/specification/set/presenter_spec.rb
+++ b/spec/specification/set/presenter_spec.rb
@@ -5,7 +5,7 @@ module Pod
 
     describe 'Set Information' do
       before do
-        set = Source::Aggregate.new(fixture('spec-repos')).search_by_name('JSONKit').first
+        set = Source::Aggregate.new([fixture('spec-repos/master'), fixture('spec-repos/test_repo')]).search_by_name('JSONKit').first
         @presenter = Spec::Set::Presenter.new(set)
       end
 
diff --git a/spec/specification/set_spec.rb b/spec/specification/set_spec.rb
index 4aecebd30..31dc14394 100644
--- a/spec/specification/set_spec.rb
+++ b/spec/specification/set_spec.rb
@@ -109,7 +109,8 @@ module Pod
 
       before do
         # JSONKit is in test repo has version 1.4 (duplicated) and the 999.999.999.
-        @set = Source::Aggregate.new(fixture('spec-repos')).search_by_name('JSONKit').first
+        repos_dirs = [fixture('spec-repos/master'), fixture('spec-repos/test_repo')]
+        @set = Source::Aggregate.new(repos_dirs).search_by_name('JSONKit').first
       end
 
       it 'returns the sources where a podspec is available' do