diff --git a/src/paveit/datamodels/labworks.py b/src/paveit/datamodels/labworks.py
new file mode 100644
index 0000000..63917b6
--- /dev/null
+++ b/src/paveit/datamodels/labworks.py
@@ -0,0 +1,27 @@
+from .tasks import TaskManagerBase
+from mongoengine import *
+
+
+# Vorbereitungen Performance Untersuchungen
+class LabworksDrillRoad(TaskManagerBase):
+    pass
+
+class LabworksMakingAsphaltSlabs(TaskManagerBase):
+    pass
+
+class LabworksDrillAsphaltSlabs(TaskManagerBase):
+    pass
+
+class LabworksSawDrillCores(TaskManagerBase):
+    pass
+
+class LabworksGrindingAsphaltSamples(TaskManagerBase):
+    pass
+
+class LabworksDetermineDensity(TaskManagerBase):
+    pass
+
+class LabworksDetermineGeometry(TaskManagerBase):
+    pass
+
+
diff --git a/src/paveit/datamodels/taskmanager.py b/src/paveit/datamodels/taskmanager.py
index 808599f..1da1d26 100755
--- a/src/paveit/datamodels/taskmanager.py
+++ b/src/paveit/datamodels/taskmanager.py
@@ -3,13 +3,13 @@ import datetime
 
 from mongoengine import *
 
+from .client import Client
+from .enumeration import ProcessStatusEnum
 from .machines import MachineBase
 from .material import Material
 from .project import Project
 from .usermanagement import Organisation, User
 from .workpackage import Workpackage
-from .enumeration import ProcessStatusEnum
-from .client import Client
 
 
 class TaskManagerBase(Document):
@@ -34,6 +34,9 @@ class TaskManagerBase(Document):
     
     series = StringField(default='Serie 01')
     
+    step_before = ListField(LazyReferenceField('self'), required=False)
+    step_after = ListField(LazyReferenceField('self'), required=False)
+    
     meta = {
         'allow_inheritance': True,
         'index_opts': {},