diff --git a/usrguide/apiguide/7-references.adoc b/usrguide/apiguide/7-references.adoc
index 11b68e60463885f84d03067645a84fa2f5196ffc..cdc359eb2ccb0901a14e64124f7fc0fe90cad4b1 100644
--- a/usrguide/apiguide/7-references.adoc
+++ b/usrguide/apiguide/7-references.adoc
@@ -6,30 +6,44 @@
 [[_2]]
 * [2] link:https://www.etsi.org/deliver/etsi_es/201800_201899/20187304/04.01.01_60/es_20187304v040101p.pdf[Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3. Part 4: TTCN–3 Operational SemanticsEuropean Telecommunications Standards Institute. ES 201 873-4 Version 4.1.1, June 2009]
 
-3. link:https://pdfs.semanticscholar.org/33b5/877c85f7fd4f35c7f58c39121358c3652966.pdf[Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3. Part 7: Using ASN.1 with TTCN–3 European Telecommunications Standards Institute. ES 201 873-7 Version 4.5.1, April 2013]
+[[_3]]
+* [3] link:https://pdfs.semanticscholar.org/33b5/877c85f7fd4f35c7f58c39121358c3652966.pdf[Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3. Part 7: Using ASN.1 with TTCN–3 European Telecommunications Standards Institute. ES 201 873-7 Version 4.5.1, April 2013]
 
-4. link:https://www.etsi.org/deliver/etsi_ES/201800_201899/20187309/04.05.01_60/es_20187309v040501p.pdf[Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3. Part 9: Using XML Schema with TTCN–3 European Telecommunications Standards Institute. ES 201 873-9 Version 4.5.1, April 2013]
+[[_4]]
+* [4] link:https://www.etsi.org/deliver/etsi_ES/201800_201899/20187309/04.05.01_60/es_20187309v040501p.pdf[Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3. Part 9: Using XML Schema with TTCN–3 European Telecommunications Standards Institute. ES 201 873-9 Version 4.5.1, April 2013]
 
-5. link:https://www.itu.int/rec/T-REC-X.690-200811-S[ITU-T, X.690, Information TechnologyASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)International Telecommunication Union, November 2008]
+[[_5]]
+* [5] link:https://www.itu.int/rec/T-REC-X.690-200811-S[ITU-T, X.690, Information TechnologyASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)International Telecommunication Union, November 2008]
 
-6. ITU-T, X.693, Information TechnologyASN.1 encoding rules: XML Encoding Rules (XER), November 2008
+[[_6]]
+* [6] link:https://www.itu.int/rec/T-REC-X.693-200811-S[ITU-T, X.693, Information TechnologyASN.1 encoding rules: XML Encoding Rules (XER), November 2008]
+
+[[_7]]
+* [7] link:https://www.itu.int/rec/T-REC-X.693-200310-S!Amd1[ITU-T, X.693 amendment 1, Information Technology ASN.1 encoding rules: XER encoding instructions and EXTENDED-XER, October 2003]
 
-7. ITU-T, X.693 amendment 1, Information TechnologyASN.1 encoding rules: XER encoding instructions and EXTENDED-XER, November 2008
 [[_8]]
-8. ISO/IEC 10646-1, Information technology – Universal Multiple-Octet Coded Character Set (UCS) – Part 1: Architecture and Basic Multilingual Plane, Second edition, 200009-15
+* [8] ISO/IEC 10646-1, Information technology – Universal Multiple-Octet Coded Character Set (UCS) – Part 1: Architecture and Basic Multilingual Plane, Second edition, 200009-15
+
+[[_9]]
+* [9] link:https://tools.ietf.org/html/rfc3629[RFC3629: UTF-8, a transformation format of ISO 10646]
 
-9. link:https://tools.ietf.org/html/rfc3629[RFC3629: UTF-8, a transformation format of ISO 10646]
+[[_10]]
+* [10] link:https://github.com/eclipse/titan.core/blob/master/usrguide/userguide/UserGuide.adoc[User Guide for TITAN TTCN-3 Test Executor]
 
-10. link:https://github.com/eclipse/titan.core/blob/master/usrguide/userguide/UserGuide.adoc[User Guide for TITAN TTCN-3 Test Executor]
+[[_11]]
+* [11] link:https://github.com/eclipse/titan.core/blob/master/usrguide/installationguide/installationguide.adoc/[Installation guide for TITAN TTCN-3 Test Executor]
 
-11. link:https://github.com/eclipse/titan.core/blob/master/usrguide/installationguide/installationguide.adoc/[Installation guide for TITAN TTCN-3 Test Executor]
+[[_12]]
+* [12] link:https://github.com/eclipse/titan.core/blob/master/usrguide/releasenotes/releasenotes.adoc[Release Notes for TITAN TTCN-3 Test Executor]
 
-12. link:https://github.com/eclipse/titan.core/blob/master/usrguide/releasenotes/releasenotes.adoc[Release Notes for TITAN TTCN-3 Test Executor]
+[[_13]]
+* [13] link:https://github.com/eclipse/titan.core/tree/master/usrguide/referenceguide/ReferenceGuide.adoc[Technical Reference for TITAN TTCN-3 Test Executor]
 
-13. link:https://github.com/eclipse/titan.core/tree/master/usrguide/referenceguide/ReferenceGuide.adoc[Technical Reference for TITAN TTCN-3 Test Executor]
+[[_14]]
+* [14] link:http://tldp.org/HOWTO/Program-Library-HOWTO/index.html[David A. Wheeler, Program Library HOWTO]
 
-14. link:http://tldp.org/HOWTO/Program-Library-HOWTO/index.html[David A. Wheeler, Program Library HOWTO]
+[[_15]]
+* [15] link:https://www.etsi.org/deliver/etsi_es/202700_202799/202781/01.04.01_60/es_202781v010401p.pdf[ETSI ES 202 781 V1.4.1. (2015-06 Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3; TTCN-3 Language Extensions: Configuration and Deployment Support)]
 
-15. link:https://www.etsi.org/deliver/etsi_es/202700_202799/202781/01.04.01_60/es_202781v010401p.pdf[ETSI ES 202 781 V1.4.1. (2015-06 Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3; TTCN-3 Language Extensions: Configuration and Deployment Support)]
 [[_16]]
-16. link:https://www.etsi.org/deliver/etsi_es/202700_202799/202782/01.03.01_60/es_202782v010301p.pdf[ETSI ES 202 782 V1.3.1. (2015-06 Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3; TTCN-3 Language Extensions: TTCN-3 Performance and Real Time Testing)]
+* [16] link:https://www.etsi.org/deliver/etsi_es/202700_202799/202782/01.03.01_60/es_202782v010301p.pdf[ETSI ES 202 782 V1.3.1. (2015-06 Methods for Testing and Specification (MTS); The Testing and Test Control Notation version 3; TTCN-3 Language Extensions: TTCN-3 Performance and Real Time Testing)]