An inbound link is constituted by an arc from an external resource, located with a locator-type element, into an internal resource. The diagram below illustrates the composition of an extended link. Putting together all the previous elements, we finally have a complete and valid extended link. This was included in order to have a standard way for applications to express complex titles that include more than a string. The contents of title-type elements are not constrained by XLink.
Simple links are, conceptually, a subset of extended links.
They exist as a notation for links where you don't need the overhead of an entire extended link. That's all there is to it. We have covered all the types and attributes of XLink. As you can see, this is a powerful but compact specification that is bound to prove useful in future projects. We will wrap up by presenting some pointers to useful XLink tools.