<?xml version="1.0" encoding="utf-8"?>
<!--
  This file is part of the OCW taxonomy, which is an extension on the Dutch taxonomy (NT, Nederlandse Taxonomie) 
  Intellectual Property of the State of the Netherlands, Ministry of Culture, Education and Sciences (OCW, Ministerie van Onderwijs, Cultuur en Wetenschappen)
  Architecture: NT13 
  Version: 20190220.a
  Released by: Dienst Uitvoering Onderwijs (DUO)
  Release date: Mon Aug 27 08:07:52 CET 2018
-->
<link:linkbase xmlns:gen="http://xbrl.org/2008/generic" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:va="http://xbrl.org/2008/assertion/value" xmlns:validation="http://xbrl.org/2008/validation" xmlns:variable="http://xbrl.org/2008/variable" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xfi="http://www.xbrl.org/2008/function/instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd   http://www.w3.org/1999/xlink http://www.xbrl.org/2003/xlink-2003-12-31.xsd   http://xbrl.org/2008/generic http://www.xbrl.org/2008/generic-link.xsd   http://xbrl.org/2008/validation http://www.xbrl.org/2008/validation.xsd   http://xbrl.org/2008/variable http://www.xbrl.org/2008/variable.xsd   http://xbrl.org/2008/assertion/value http://www.xbrl.org/2008/value-assertion.xsd      ">
	<link:arcroleRef arcroleURI="http://xbrl.org/arcrole/2008/variable-set" xlink:href="http://www.xbrl.org/2008/variable.xsd#variable-set" xlink:type="simple"/>
	<link:arcroleRef arcroleURI="http://xbrl.org/arcrole/2008/assertion-set" xlink:href="http://www.xbrl.org/2008/validation.xsd#assertion-set" xlink:type="simple"/>
	<link:arcroleRef arcroleURI="http://xbrl.org/arcrole/2016/assertion-unsatisfied-severity" xlink:href="http://www.xbrl.org/2016/assertion-severity.xsd#assertion-unsatisfied-severity" xlink:type="simple"/>
	<link:roleRef roleURI="http://www.xbrl.org/2008/role/link" xlink:href="http://www.xbrl.org/2008/generic-link.xsd#standard-link-role" xlink:type="simple"/>
	<gen:link xlink:role="http://www.xbrl.org/2008/role/link" xlink:type="extended">
		<validation:assertionSet id="assertion-set-general" xlink:label="assertion-set-general" xlink:type="resource"/>
		<gen:arc xlink:arcrole="http://xbrl.org/arcrole/2008/assertion-set" xlink:from="assertion-set-general" xlink:to="va-BR-OCW-WNT.S.1-durationperiod" xlink:type="arc"/>
		<va:valueAssertion aspectModel="dimensional" id="va-BR-OCW-WNT.S.1-durationperiod" implicitFiltering="false" test="count($InvalidPeriods) eq 0" xlink:label="va-BR-OCW-WNT.S.1-durationperiod" xlink:type="resource"/>
		<variable:variableArc name="InvalidPeriods" xlink:arcrole="http://xbrl.org/arcrole/2008/variable-set" xlink:from="va-BR-OCW-WNT.S.1-durationperiod" xlink:to="v_InvalidPeriods" xlink:type="arc"/>
		<variable:generalVariable bindAsSequence="true" select="/xbrli:xbrl/xbrli:context/xbrli:period[not(xfi:is-start-end-period(.)) or not(xs:date(xbrli:startDate) eq $CurrentPeriodStartDate) or not(xs:date(xbrli:endDate) eq $CurrentPeriodEndDate)]" xlink:label="v_InvalidPeriods" xlink:type="resource"/>
		<gen:arc xlink:arcrole="http://xbrl.org/arcrole/2016/assertion-unsatisfied-severity" xlink:from="va-BR-OCW-WNT.S.1-durationperiod" xlink:to="sev_ERROR_loc" xlink:type="arc"/>
		<link:loc xlink:href="http://www.xbrl.org/2016/severities.xml#ERROR" xlink:label="sev_ERROR_loc" xlink:type="locator"/>
	</gen:link>
</link:linkbase>