This schema describes a REFERENCE element intended for
use in family tree documents. It was developed as an
example for Chapter 25 of the XML Bible, 3rd Edition, by
Elliotte Rusty Harold (elharo@metalab.unc.edu)
Published by Wiley 2004. ISBN 0-7645-4986-3.
This schema is placed in the public domain. Please
feel free to use it or adapt it in any way you like.
The SourceType is used exclusively for REFERENCE
elements. Each such element has a unique ID attribute
by which it can be referred to, and PCDATA content
identifying the source of the information; e.g.,
a document, an interview, personal recollection, etc.