XML Validation

[Sri Yasasvi]

Hi

I am getting the following error when i trying to validate XML document.

Unable to locate a reference to a supported schema type (DTD, W3C Schema) within this document instance.

<?xml version="1.0" encoding="UTF-8"?>
<people xmlns:xi="http://www.w3.org/2001/XInclude">
<xi:include href="Alanturing.xml"/>
<xi:include href="RichardPFeyman.xml"/>
</people>

Could you please tell me what is wrong in this document.


Thanks,
Sri