diff --git a/models/tapi/src/main/yang/tapi-path-computation@2018-03-07.yang b/models/tapi/src/main/yang/tapi-path-computation@2018-03-07.yang
index fa5745b..6c91d5e 100644
--- a/models/tapi/src/main/yang/tapi-path-computation@2018-03-07.yang
+++ b/models/tapi/src/main/yang/tapi-path-computation@2018-03-07.yang
@@ -8,10 +8,10 @@
         prefix tapi-common;
     }
     organization "ONF OTCC (Open Transport Configuration & Control) Project";
-    contact "
-        Project Web: <https://wiki.opennetworking.org/display/OTCC/TAPI>
-        Project List: <mailto:transport-api@opennetworking.org>
-        Editor: Karthik Sethuraman
+    contact "
+        Project Web: <https://wiki.opennetworking.org/display/OTCC/TAPI>
+        Project List: <mailto:transport-api@opennetworking.org>
+        Editor: Karthik Sethuraman
                 <mailto:karthik.sethuraman@necam.com>";
     description "
         This module contains TAPI Path Computation Model definitions.
@@ -19,11 +19,11 @@
         Copyright (c) 2018 Open Networking Foundation (ONF). All rights reserved.
         License: This module is distributed under the Apache License 2.0";
     revision 2018-03-07 {
-        description "ONF Transport API version 2.0.2
-        This YANG module has been generated from the TAPI UML Model using the IISOMI-Eagle xmi2yang mapping tool version .
-        <https://wiki.opennetworking.org/display/OIMT/IISOMI>
+        description "ONF Transport API version 2.0.2
+        This YANG module has been generated from the TAPI UML Model using the IISOMI-Eagle xmi2yang mapping tool version .
+        <https://wiki.opennetworking.org/display/OIMT/IISOMI>
         Changes in this revision: <https://github.com/OpenNetworkingFoundation/TAPI/blob/develop/change-log.md>";
-        reference "ONF-TR-527, ONF-TR-512, ONF-TR-531, RFC 6020, RFC 6087 and ONF TAPI UML model
+        reference "ONF-TR-527, ONF-TR-512, ONF-TR-531, RFC 6020, RFC 6087 and ONF TAPI UML model
                   <https://github.com/OpenNetworkingFoundation/TAPI/tree/develop/UML>";
     }
     augment "/tapi-common:context" {
@@ -39,12 +39,14 @@
             type leafref {
                 path '/tapi-common:context/tapi-path-computation:path/tapi-path-computation:uuid';
             }
+            description "none";
         }
+        description "none";
     }
 
     /***********************
     * package object-classes
-    **********************/
+    **********************/ 
         grouping path {
             list link {
                 uses tapi-topology:link-ref;
@@ -62,10 +64,8 @@
             description "Path is described by an ordered list of TE Links. A TE Link is defined by a pair of Node/NodeEdgePoint IDs. A Connection is realized by concatenating link resources (associated with a Link) and the lower-level connections (cross-connections) in the different nodes";
         }
         grouping path-service-end-point {
-            leaf service-interface-point {
-                type leafref {
-                    path '/tapi-common:context/tapi-common:service-interface-point/tapi-common:uuid';
-                }
+            container service-interface-point {
+            	uses tapi-common:service-interface-point-ref;
                 config false;
                 description "none";
             }
@@ -86,11 +86,11 @@
             }
             uses tapi-common:local-class;
             description "The association of the FC to LTPs is made via EndPoints.
-                The EndPoint (EP) object class models the access to the FC function.
-                The traffic forwarding between the associated EPs of the FC depends upon the type of FC and may be associated with FcSwitch object instances.
-                In cases where there is resilience the EndPoint may convey the resilience role of the access to the FC.
+                The EndPoint (EP) object class models the access to the FC function. 
+                The traffic forwarding between the associated EPs of the FC depends upon the type of FC and may be associated with FcSwitch object instances.  
+                In cases where there is resilience the EndPoint may convey the resilience role of the access to the FC. 
                 It can represent a protected (resilient/reliable) point or a protecting (unreliable working or protection) point.
-                The EP replaces the Protection Unit of a traditional protection model.
+                The EP replaces the Protection Unit of a traditional protection model. 
                 The ForwadingConstruct can be considered as a component and the EndPoint as a Port on that component";
         }
         grouping path-computation-service {
@@ -195,10 +195,9 @@
                 config false;
                 description "none";
             }
-            leaf-list avoid-topology {
-                type leafref {
-                    path '/tapi-common:context/tapi-topology:topology/tapi-topology:uuid';
-                }
+            list avoid-topology {
+                uses tapi-topology:topology-ref;
+                key 'topology-id';
                 config false;
                 description "none";
             }