labelType definition. If a 'from' or 'to' attribute value is supplied, it MUST correspond to the same value for some 'label' attribute on a 'locator-' or 'resource-' type element that appears as a direct child inside the same extended-type element as does the arc-type element. See also 'from' and 'to' type definitions.
token
<simpleType name="labelType" >
<restriction base="token" />
</simpleType>