diff --git a/app/controllers/wiki_controller.rb b/app/controllers/wiki_controller.rb
index c1d5993..be2f605 100644
--- a/app/controllers/wiki_controller.rb
+++ b/app/controllers/wiki_controller.rb
@@ -100,8 +100,8 @@ class WikiController < ApplicationController
 	end
 
 	def versions
-		@history_to = params[:to] || @wiki_page.versions.count
-		@history_from = params[:from] || @wiki_page.versions.count - 1
+		@history_to = params[:to] || @wiki_page.versions[-1].version
+		@history_from = params[:from] || (@wiki_page.versions.count > 1 ? @wiki_page.versions[-2].version : @history_to)
 		@offset = params[:offset] || 0
 
 		respond_to do |format|
diff --git a/app/models/attachment.rb b/app/models/attachment.rb
index 87288c4..8e7e42b 100644
--- a/app/models/attachment.rb
+++ b/app/models/attachment.rb
@@ -18,9 +18,14 @@ require 'fileutils.rb'
 
 class Attachment < ActiveRecord::Base
 
+	# Plugins
+	acts_as_paranoid
+
+	# Associacoes
 	belongs_to :course
+
+	# Validacao
 	generate_validations
-	acts_as_paranoid
 
 	# Atributo virtual file
 	def file=(new_file)
diff --git a/app/models/course.rb b/app/models/course.rb
index 809a296..06e1393 100644
--- a/app/models/course.rb
+++ b/app/models/course.rb
@@ -16,10 +16,13 @@
 
 class Course < ActiveRecord::Base
 
+	# Plugins
+	acts_as_paranoid
+	
 	# Associacoes
 	has_many :attachments,
 	         :order => "file_name",
-	          :dependent => :destroy
+	         :dependent => :destroy
 
 	has_many :events,
 	         :order => "time asc",
@@ -27,8 +30,8 @@ class Course < ActiveRecord::Base
 
 	has_many :news,
 	         :foreign_key => "receiver_id",
-	        :order => "id desc",
-	        :dependent => :destroy
+	         :order => "id desc",
+	         :dependent => :destroy
 
 	has_many :log_entries,
 	         :order => "created_at desc",
@@ -37,10 +40,7 @@ class Course < ActiveRecord::Base
 	has_many :wiki_pages,
 	         :order => "position",
 	         :dependent => :destroy
-
-	# Plugins
-	acts_as_paranoid
-
+	
 	# Validacao
 	generate_validations
 	validates_uniqueness_of :short_name
diff --git a/app/models/event.rb b/app/models/event.rb
index ff94bab..cf6916e 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -15,12 +15,16 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class Event < ActiveRecord::Base
-
+	
+	# Plugins
 	acts_as_paranoid
-	generate_validations
 
+	# Associacoes
 	belongs_to :course
 
+	# Validacao
+	generate_validations
+
 	def Event.to_ical(courses)
 		courses = [courses] unless courses.kind_of?(Array)
 		cal = Icalendar::Calendar.new
diff --git a/app/models/log_entry.rb b/app/models/log_entry.rb
index ceb4746..f2fa95b 100644
--- a/app/models/log_entry.rb
+++ b/app/models/log_entry.rb
@@ -15,11 +15,14 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class LogEntry < ActiveRecord::Base
-	belongs_to :user
-	belongs_to :course
 
+	# Plugins
 	acts_as_paranoid
 
+	# Associacoes
+	belongs_to :course
+	belongs_to :user, :with_deleted => true
+
 	def reversible?() false end
 
 	def to_xml(options = {})
diff --git a/app/models/log_entry/attachment_log_entry.rb b/app/models/log_entry/attachment_log_entry.rb
index 44a00b3..f38429d 100644
--- a/app/models/log_entry/attachment_log_entry.rb
+++ b/app/models/log_entry/attachment_log_entry.rb
@@ -15,21 +15,18 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class AttachmentLogEntry < LogEntry
-	def attachment
-		Attachment.find_with_deleted(target_id)
-	end
+	belongs_to :attachment,
+               :foreign_key => "target_id",
+               :with_deleted => true
 end
 
 class AttachmentDeleteLogEntry < AttachmentLogEntry
 	def reversible?()
-		a = Attachment.find_with_deleted(target_id)
-		a.deleted_at != nil
+        attachment.deleted?
 	end
 	def undo!(current_user)
-		a = Attachment.find_with_deleted(target_id)
-		a.update_attribute(:deleted_at, nil)
-		AttachmentRestoreLogEntry.create!(:target_id => a.id, :user_id => current_user.id,
-				:course => a.course)
+		attachment.update_attribute(:deleted_at, nil)
+		AttachmentRestoreLogEntry.create!(:target_id => attachment.id, :user_id => current_user.id, :course => attachment.course)
 	end
 end
 
diff --git a/app/models/log_entry/event_log_entry.rb b/app/models/log_entry/event_log_entry.rb
index 4937cca..45d1731 100644
--- a/app/models/log_entry/event_log_entry.rb
+++ b/app/models/log_entry/event_log_entry.rb
@@ -15,21 +15,18 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class EventLogEntry < LogEntry
-	def event
-		Event.find_with_deleted(target_id)
-	end
+	belongs_to :event,
+               :foreign_key => "target_id",
+               :with_deleted => true
 end
 
 class EventDeleteLogEntry < EventLogEntry
 	def reversible?()
-		e = Event.find_with_deleted(target_id)
-		e.deleted_at != nil
+        event.deleted?
 	end
 	def undo!(current_user)
-		e = Event.find_with_deleted(target_id)
-		e.update_attribute(:deleted_at, nil)
-		EventRestoreLogEntry.create!(:target_id => e.id, :user_id => current_user.id,
-				:course_id => e.course_id)
+		event.update_attribute(:deleted_at, nil)
+		EventRestoreLogEntry.create!(:target_id => event.id, :user_id => current_user.id, :course => event.course)
 	end
 end
 
diff --git a/app/models/log_entry/news_log_entry.rb b/app/models/log_entry/news_log_entry.rb
index 404380c..c0196eb 100644
--- a/app/models/log_entry/news_log_entry.rb
+++ b/app/models/log_entry/news_log_entry.rb
@@ -15,21 +15,18 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class NewsLogEntry < LogEntry
-	def news
-		News.find_with_deleted(target_id)
-	end
+	belongs_to :news,
+               :foreign_key => "target_id",
+               :with_deleted => true
 end
 
 class NewsDeleteLogEntry < NewsLogEntry
 	def reversible?()
-		n = News.find_with_deleted(target_id)
-		n.deleted_at != nil
+        news.deleted?
 	end
 	def undo!(current_user)
-		n = News.find_with_deleted(target_id)
-		n.update_attribute(:deleted_at, nil)
-		NewsRestoreLogEntry.create!(:target_id => n.id, :user_id => current_user.id,
-				:course => n.course)
+		news.update_attribute(:deleted_at, nil)
+		NewsRestoreLogEntry.create!(:target_id => news.id, :user_id => current_user.id, :course => news.course)
 	end
 end
 
diff --git a/app/models/log_entry/wiki_log_entry.rb b/app/models/log_entry/wiki_log_entry.rb
index e75ee8e..342ed6c 100644
--- a/app/models/log_entry/wiki_log_entry.rb
+++ b/app/models/log_entry/wiki_log_entry.rb
@@ -15,11 +15,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class WikiLogEntry < LogEntry
-	def wiki_page
-		w = WikiPage.find_with_deleted(target_id)
-		w.revert_to(version)
-		return w
-	end
+	belongs_to :wiki_page,
+	           :foreign_key => "target_id",
+	           :with_deleted => true
 end
 
 class WikiEditLogEntry < WikiLogEntry
@@ -28,16 +26,12 @@ end
 
 class WikiDeleteLogEntry < WikiLogEntry
 	def reversible?()
-		w = WikiPage.find_with_deleted(target_id)
-		w.deleted_at != nil
+		wiki_page.deleted?
 	end
 	def undo!(current_user)
-		w = WikiPage.find_with_deleted(target_id)
-		w.update_attribute(:deleted_at, nil)
-		w.position = w.course.wiki_pages.maximum(:position) + 1
-		w.save!
-		WikiRestoreLogEntry.create!(:target_id => w.id, :user_id => current_user.id,
-				:course => w.course)
+		wiki_page.update_attribute(:deleted_at, nil)
+		wiki_page.update_attribute(:position, wiki_page.course.wiki_pages.maximum(:position) + 1)
+		WikiRestoreLogEntry.create!(:target_id => wiki_page.id, :user_id => current_user.id, :course => wiki_page.course)
 	end
 end
 
diff --git a/app/models/message.rb b/app/models/message.rb
index f3a6043..034fe45 100644
--- a/app/models/message.rb
+++ b/app/models/message.rb
@@ -15,28 +15,19 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 class Message < ActiveRecord::Base
-	acts_as_paranoid
-	belongs_to :user,   :foreign_key => "sender_id"
-end
 
+	# Plugins
+	acts_as_paranoid
+	
+	# Associacoes
+	belongs_to :user,
+	           :foreign_key => "sender_id",
+	           :with_deleted => true
 
-class PrivateMessage < Message
 end
 
-
 class News < Message
 	validates_presence_of :title
-	belongs_to :course, :foreign_key => "receiver_id"
-end
-
-
-class ShoutboxMessage < Message
-end
-
-
-class CourseShoutboxMessage < ShoutboxMessage
-end
-
-
-class UserShoutboxMessage < ShoutboxMessage
+	belongs_to :course,
+	           :foreign_key => "receiver_id"
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index 7dda15f..ba1bcdd 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -18,10 +18,13 @@ require 'digest/sha1'
 
 class User < ActiveRecord::Base
 
+	# Plugins
 	acts_as_paranoid
 
+	# Associacoes
 	has_and_belongs_to_many :courses, :order => 'full_name'
 
+	# Validacao
 	validates_length_of       :login, :within => 3..40
 	validates_length_of       :name,  :within => 3..40
 	validates_length_of       :display_name, :within => 3..40
@@ -35,6 +38,7 @@ class User < ActiveRecord::Base
 	validates_format_of :email,
 			:with => /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i
 
+	# Seguranca
 	attr_protected :id, :salt
 	attr_accessor :password, :password_confirmation
 
diff --git a/app/models/wiki_page.rb b/app/models/wiki_page.rb
index e2252e1..dab96a0 100644
--- a/app/models/wiki_page.rb
+++ b/app/models/wiki_page.rb
@@ -19,25 +19,29 @@ require 'tempfile'
 
 class WikiPage < ActiveRecord::Base
 
+	# Plugins
+	acts_as_paranoid
+	acts_as_list :scope => 'course_id = #{course_id}'
+	acts_as_versioned :if_changed => [ :content, :description, :title ]
+	self.non_versioned_fields << 'position'
+
+	# Associacoes
 	belongs_to :course
-	belongs_to :user
+	belongs_to :user, :with_deleted => true
 
+	# Valicacao
 	generate_validations
 	validates_uniqueness_of :title, :scope => :course_id
 	validates_format_of :title, :with => /^[^0-9]/
 
-	acts_as_paranoid
-	acts_as_list :scope => 'course_id = #{course_id}'
-	acts_as_versioned :if_changed => [ :content, :description, :title ]
-	self.non_versioned_fields << 'position'
 
-    def validate
-        begin
-            to_html
-        rescue
-            errors.add("content", "possui erro de sintaxe")
-        end
-    end
+	def validate
+		begin
+			to_html
+		rescue
+			errors.add("content", "possui erro de sintaxe")
+		end
+	end
 
 	def to_html(text = self.content)
 		return BlueCloth.new(text).to_html
diff --git a/app/views/log/_wiki_log_entry.html.haml b/app/views/log/_wiki_log_entry.html.haml
index 78db92d..144042b 100644
--- a/app/views/log/_wiki_log_entry.html.haml
+++ b/app/views/log/_wiki_log_entry.html.haml
@@ -1,13 +1,21 @@
-= "Página " + link_to(h(entry.wiki_page.versions.last.title), course_wiki_url(entry.course, entry.wiki_page.id, :version => entry.wiki_page.version))
+= "Página " + link_to(h(entry.wiki_page.title), course_wiki_url(entry.course, entry.wiki_page.id, :version => entry.version))
 
 = "criada "     if entry.kind_of?(WikiCreateLogEntry)
 = "editada "    if entry.kind_of?(WikiEditLogEntry)
 = "excluída "   if entry.kind_of?(WikiDeleteLogEntry)
 = "restaurada " if entry.kind_of?(WikiRestoreLogEntry)
 
+- current_version = WikiPage.find_version(entry.wiki_page.id, entry.version)
+- previous_version = entry.wiki_page.previous_version(entry.version)
+
 - if entry.kind_of?(WikiEditLogEntry)
-  - if entry.wiki_page.description and !entry.wiki_page.description.empty?
-    = "(<i>#{h(entry.wiki_page.description)}</i>)"
-  = "(" + link_to("diff", diff_course_wiki_url(entry.course, entry.wiki_page.id, :from => entry.wiki_page.version - 1, :to => entry.wiki_page.version)) + ")" 
-  = "(" + link_to("edit", edit_course_wiki_url(entry.course, entry.wiki_page.id, :description => "Revertendo para versão #{entry.wiki_page.version}", :version => entry.wiki_page.version)) + ")"
-  = "(" + link_to("undo", edit_course_wiki_url(entry.course, entry.wiki_page.id, :description => "Revertendo para versão #{entry.wiki_page.version-1}", :version => entry.wiki_page.version - 1)) + ")"
+  - if current_version.description and !current_version.description.empty?
+    = "(<i>#{h(current_version.description)}</i>)"
+
+  - unless previous_version.nil?
+    = "(" + link_to("diff", diff_course_wiki_url(entry.course, entry.wiki_page.id, :from => previous_version.version, :to => entry.version)) + ")" 
+  
+  = "(" + link_to("edit", edit_course_wiki_url(entry.course, entry.wiki_page.id, :description => "Revertendo para versão #{entry.version}", :version => entry.version)) + ")"
+  
+  - unless previous_version.nil?
+    = "(" + link_to("undo", edit_course_wiki_url(entry.course, entry.wiki_page.id, :description => "Revertendo para versão #{previous_version.version}", :version => previous_version.version)) + ")"
diff --git a/app/views/wiki/versions.html.haml b/app/views/wiki/versions.html.haml
index a778f2d..eb4d8f8 100644
--- a/app/views/wiki/versions.html.haml
+++ b/app/views/wiki/versions.html.haml
@@ -25,7 +25,7 @@
           %td.narrow
             %input{:type => "radio", :name => "to", :value => entry.version, :onclick => %"history_to(#{entry.version})"}
           %td= link_to(tz(entry.updated_at).strftime("%d/%m/%y&nbsp;%H:%M:%S"), course_wiki_url(@course, @wiki_page, :version => entry.version))
-          %td= link_to truncate(h(User.find(entry.user_id).display_name), 20), user_path(User.find(entry.user_id))
+          %td= link_to truncate(h(User.find_with_deleted(entry.user_id).display_name), 20), user_path(User.find_with_deleted(entry.user_id))
           %td
             = entry.description
             - if (entry.version > @wiki_page.versions.minimum(:version))
diff --git a/test/unit/user_test.rb b/test/unit/user_test.rb
index 38725f8..ec56f27 100644
--- a/test/unit/user_test.rb
+++ b/test/unit/user_test.rb
@@ -234,4 +234,14 @@ class UserTest < Test::Unit::TestCase
 		assert_not_equal "I-want-to-set-my-salt", u.salt
 		assert_equal "verybadbob", u.login
 	end
+
+	def test_paranoid
+		assert User.paranoid?
+
+		u = users(:bob)
+		u.destroy
+
+		assert_raises(ActiveRecord::RecordNotFound) { User.find(u.id) }
+		assert_nothing_raised { User.find_with_deleted(u.id) }
+	end
 end
diff --git a/vendor/gems/acts_as_versioned-0.2.3/lib/acts_as_versioned.rb b/vendor/gems/acts_as_versioned-0.2.3/lib/acts_as_versioned.rb
index 24f3b42..9b81912 100644
--- a/vendor/gems/acts_as_versioned-0.2.3/lib/acts_as_versioned.rb
+++ b/vendor/gems/acts_as_versioned-0.2.3/lib/acts_as_versioned.rb
@@ -279,6 +279,10 @@ module ActiveRecord #:nodoc:
           end          
         end
 
+        def previous_version(current_version = self.version)
+            self.versions.find(:first, :conditions => [ 'version < ?', current_version ], :order => 'version desc')
+        end
+
         protected
         # sets the new version before saving, unless you're using optimistic locking.  In that case, let it take care of the version.
         def set_new_version
@@ -394,4 +398,4 @@ module ActiveRecord #:nodoc:
   end
 end
 
-ActiveRecord::Base.class_eval { include ActiveRecord::Acts::Versioned }
\ No newline at end of file
+ActiveRecord::Base.class_eval { include ActiveRecord::Acts::Versioned }