diff --git a/cybertools/knowledge/element.py b/cybertools/knowledge/element.py
index e743312..957151c 100644
--- a/cybertools/knowledge/element.py
+++ b/cybertools/knowledge/element.py
@@ -1,35 +1,15 @@
-#
-#  Copyright (c) 2006 Helmut Merz helmutm@cy55.de
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, write to the Free Software
-#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
+# cybertools.knowledge.element
 
-"""
-Represent knowledge elements and their interrelations.
-
-$Id$
+""" Represent knowledge elements and their interrelations.
 """
 
-from zope.interface import implements
+from zope.interface import implementer
 from cybertools.knowledge.interfaces import IKnowledgeElement
 
 
+@implementer(IKnowledgeElement)
 class KnowledgeElement(object):
 
-    implements(IKnowledgeElement)
-    
     def __init__(self):
         self._parent = None
         self._dependencies = {}
diff --git a/cybertools/knowledge/knowing.py b/cybertools/knowledge/knowing.py
index 48248dd..36a1142 100644
--- a/cybertools/knowledge/knowing.py
+++ b/cybertools/knowledge/knowing.py
@@ -1,35 +1,15 @@
-#
-#  Copyright (c) 2006 Helmut Merz helmutm@cy55.de
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, write to the Free Software
-#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
+# cybertools.knowledge.knowing
 
-"""
-Manage objects (people) who know something.
-
-$Id$
+""" Manage objects (people) who know something.
 """
 
-from zope.interface import implements
+from zope.interface import implementer
 from cybertools.knowledge.interfaces import IKnowing
 
 
+@implementer(IKnowing)
 class Knowing(object):
 
-    implements(IKnowing)
-
     def __init__(self):
         self._knowledge = {}
 
diff --git a/cybertools/knowledge/provider.py b/cybertools/knowledge/provider.py
index e64025d..266a5e2 100644
--- a/cybertools/knowledge/provider.py
+++ b/cybertools/knowledge/provider.py
@@ -1,35 +1,15 @@
-#
-#  Copyright (c) 2006 Helmut Merz helmutm@cy55.de
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, write to the Free Software
-#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
+# cybertools.knowledge.provider
 
-"""
-Knowledge providers provide knowledge.
-
-$Id$
+""" Knowledge providers provide knowledge.
 """
 
-from zope.interface import implements
+from zope.interface import implementer
 from cybertools.knowledge.interfaces import IKnowledgeProvider
 
 
+@implementer(IKnowledgeProvider)
 class KnowledgeProvider(object):
 
-    implements(IKnowledgeProvider)
-    
     def __init__(self):
         self._providedKnowledge = {}
 
diff --git a/cybertools/knowledge/requirement.py b/cybertools/knowledge/requirement.py
index d57efee..c73ffce 100644
--- a/cybertools/knowledge/requirement.py
+++ b/cybertools/knowledge/requirement.py
@@ -1,35 +1,15 @@
-#
-#  Copyright (c) 2006 Helmut Merz helmutm@cy55.de
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, write to the Free Software
-#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-#
+# cybertools.knowledge.requirement
 
-"""
-Represent positions that require certain knowledge.
-
-$Id$
+""" Represent positions that require certain knowledge.
 """
 
-from zope.interface import implements
+from zope.interface import implementer
 from cybertools.knowledge.interfaces import IRequirementProfile
 
 
+@implementer(IRequirementProfile)
 class RequirementProfile(object):
 
-    implements(IRequirementProfile)
-    
     def __init__(self):
         self._requirements = {}