<?xml version="1.0" encoding="UTF-8"?> <!ELEMENT books (book+, totalCost, customer)> <!ELEMENT book (bookInfo, salesInfo)> <!ATTLIST book contentType (Fiction | Nonfiction) #REQUIRED format (Hardback | Paperback) #REQUIRED> <!ELEMENT bookInfo (title, author, publisher, isbn)> <!ELEMENT title (#PCDATA)> <!ELEMENT author (#PCDATA)> <!ELEMENT publisher (#PCDATA)> <!ELEMENT isbn (#PCDATA)> <!ELEMENT salesInfo (price, itemNumber, date, source, shipping, cost)> <!ELEMENT price (#PCDATA)> <!ATTLIST price priceType (Retail | Wholesale) #REQUIRED> <!ELEMENT itemNumber (#PCDATA)> <!ELEMENT date (#PCDATA)> <!ELEMENT source EMPTY> <!ATTLIST source sourceType (Retail | Wholesale) #REQUIRED> <!ELEMENT shipping (#PCDATA)> <!ELEMENT cost (#PCDATA)> <!ELEMENT totalCost (#PCDATA)> <!ELEMENT customer (custNumber, lastName, firstName, address, city, state, zip, phone, email)> <!ATTLIST customer custType (newRetail | prevRetail | newWholesale | prevWholesale) #REQUIRED> <!ELEMENT custNumber (#PCDATA)> <!ELEMENT lastName (#PCDATA)> <!ELEMENT firstName (#PCDATA)> <!ELEMENT address (#PCDATA)> <!ELEMENT city (#PCDATA)> <!ELEMENT state (#PCDATA)> <!ELEMENT zip (#PCDATA)> <!ELEMENT phone (#PCDATA)> <!ELEMENT email (#PCDATA)>