| Rule Description | Element Content |
|---|---|
| EMPTY | No children allowed |
| (E*) | Any sequence of 0 or more elements E |
| (E+) | Any sequence of 1 or more elements E |
| (E?) | Optional element E (0 or 1 occurrences allowed) |
| (E1, E2, . . . ) | Element E1, followed by E2, . . . |
| (E1 | E2 | . . . ) | Element E1 or E2 or . . . |
| (#PCDATA) | Text only |
| (#PCDATA | E1 | E2 . . . )* | Any sequence of text and elements E1, E2, . . . , in any order |
| ANY | Any children allowed |