A list of acceptable pipe delimited values from which the document author
must choose.
Note that in the example below, CHICKEN is assumed by default if no
TYPE is specified.
<?xml version = "1.0"
encoding="UTF-8"
standalone = "yes"?>
<!DOCTYPE GROCERY_BASKET [
<!ELEMENT GROCERY_BASKET ANY>
<!ELEMENT MEAT EMPTY>
<!ATTLIST MEAT (CHICKEN |
BEEF |
PORK |
FISH) "CHICKEN">
]>
<GROCERY_BASKET>
<MEAT TYPE = "FISH"/>
<MEAT TYPE = "BEEF"/>
<MEAT/>
</GROCERY_BASKET>