GEDCOM Data Transfer: Moving Your Family Tree. 3rd edition. David Hawgood
If you use a computer for family history then you need to know about GEDCOM. It provides a way of moving family history information between different computer systems, and between different genealogy packages. GEDCOM is built into most genealogy software, and is also used for transferring information from databases. This book explores the basic structures and principles, to help the reader understand the process. It has a detailed description of how the files are put together, and shows how source information as well as family links can be included. There are examples from several genealogy packages, and from the Vital Records Index database.