Wireless Markup Language (WML) Document Type Definition
From:  http://www.wapforum.org/docs/WML-3-Feb-98.pdf, 980224
Section 13.2 Document Type Definition (DTD)

<!--
Wireless Markup Language (WML) Document Type Definition.
WML is an XML language. Typical usage:
<?xml version="1.0"?>
<!DOCTYPE WML PUBLIC "-//WAPFORUM//DTD WML 1.0//EN">
<WML>
...
</WML>
-->
<!ENTITY % length "CDATA"> <!-- nn for pixels or nn% for percentage
length -->
<!ENTITY % vdata "CDATA"> <!-- attribute value possibly containing
variable references -->
<!ENTITY % URL "%vdata;"> <!-- URL or URN designating a hypertext
node. May contain variable references -->
<!ENTITY % boolean "(TRUE|FALSE)">
<!ENTITY % number "NMTOKEN"> <!-- a number, with format [0-9][0-9]* -->
<!ENTITY % emph "EM | STRONG | B | I | U | BIG | SMALL">
<!ENTITY % tab "TAB">
<!ENTITY % layout "BR">
<!ENTITY % text "#PCDATA | %emph; | %tab;">
<!ENTITY % inline "%text; | %layout;">
<!-- flow covers "card-level" elements, such as text and images -->
<!ENTITY % flow "%inline; | IMG | A">
<!-- card types -->
<!ENTITY % cards "FORMCARD | DISPLAY | CHOICE | ENTRY | NODISPLAY">
<!-- tasks types -->
<!ENTITY % tasktypes "(GO|PREV|NOOP)">
<!-- task attributes -->
<!ENTITY % taskattrs "
URL %URL; #IMPLIED
VARS %vdata; #IMPLIED
SENDREFERER %boolean; 'FALSE'
METHOD (POST|GET) 'GET'
ACCEPT-CHARSET CDATA #IMPLIED
POSTDATA %vdata; #IMPLIED"
>
<!ENTITY % task "
TASK %tasktypes; 'GO'
%taskattrs;"
>
<!-- Navigation and event elements -->
<!ENTITY % navelmts "DO | ONEVENT">
<!--================ Decks ================-->
<!ELEMENT WML ( (COMMON, (%cards;)* ) | (%cards;)+ )>
<!ATTLIST WML
VERSION NMTOKEN #FIXED '1.0'
>
<!--================ Cards ================-->
<!-- card intrinsic events -->
<!ENTITY % cardev
"ONENTERFORWARD %URL; #IMPLIED
ONENTERBACKWARD %URL; #IMPLIED"
>
<!ENTITY % cardattrs
"NAME NMTOKEN #IMPLIED
TITLE %vdata; #IMPLIED
NEWCONTEXT %boolean; 'FALSE'
%cardev;"
>
<!-- FORMCARD field types -->
<!ENTITY % fields "%flow; | INPUT | SELECT | FIELDSET">
<!ELEMENT FORMCARD (%fields; | %navelmts;)*>
<!ATTLIST FORMCARD
%cardattrs;
STYLE (LIST|SET) 'LIST'
>
<!-- DEPRECATED -->
<!ELEMENT DISPLAY (%inline; | %navelmts;)* >
<!ATTLIST DISPLAY
%cardattrs;
>
<!-- DEPRECATED -->
<!ELEMENT CHOICE (%inline; | %navelmts; | CE)*>
<!ATTLIST CHOICE
%cardattrs;
KEY NMTOKEN #IMPLIED
DEFAULT %vdata; #IMPLIED
IKEY NMTOKEN #IMPLIED
IDEFAULT %vdata; #IMPLIED
>
<!-- DEPRECATED -->
<!ELEMENT ENTRY (%inline; | %navelmts;)*>
<!ATTLIST ENTRY
%cardattrs;
KEY NMTOKEN #REQUIRED
DEFAULT %vdata; #IMPLIED
FORMAT CDATA #IMPLIED
NOECHO %boolean; 'FALSE'
EMPTYOK %boolean; 'FALSE'
>
<!-- DEPRECATED -->
<!ELEMENT NODISPLAY (ONEVENT)* >
<!ATTLIST NODISPLAY
%cardattrs;
>
<!--================ Event Handling ================-->
<!ELEMENT DO EMPTY>
<!ATTLIST DO
TYPE CDATA #REQUIRED
LABEL %vdata; #IMPLIED
NAME NMTOKEN #IMPLIED
OPTIONAL %boolean; 'FALSE'
%task;
>
<!ELEMENT ONEVENT EMPTY>
<!ATTLIST ONEVENT
TYPE CDATA #REQUIRED
%task;
>
<!--================ Common declarations ================-->
<!ELEMENT COMMON (ACCESS | META | SCRIPT | %navelmts;)*>
<!ATTLIST COMMON
%cardev;
>
<!ELEMENT ACCESS EMPTY>
<!ATTLIST ACCESS
DOMAIN CDATA #IMPLIED
PATH CDATA #IMPLIED
PUBLIC %boolean; 'FALSE'
>
<!ELEMENT META EMPTY>
<!ATTLIST META
HTTP-EQUIV CDATA #IMPLIED
NAME CDATA #IMPLIED
USER-AGENT CDATA #IMPLIED
CONTENT CDATA #REQUIRED
SCHEME CDATA #IMPLIED
>
<!ELEMENT SCRIPT (#PCDATA)>
<!ATTLIST SCRIPT
TYPE CDATA #REQUIRED
>
<!--================ FORMCARD Fields ================-->
<!ELEMENT SELECT (OPTGROUP|OPTION)+>
<!ATTLIST SELECT
TITLE %vdata; #IMPLIED
KEY NMTOKEN #IMPLIED
DEFAULT %vdata; #IMPLIED
IKEY NMTOKEN #IMPLIED
IDEFAULT %vdata; #IMPLIED
MULTIPLE %boolean; 'FALSE'
TABINDEX %number; #IMPLIED
>
<!ELEMENT OPTGROUP (OPTGROUP|OPTION)+ >
<!ATTLIST OPTGROUP
TITLE %vdata; #IMPLIED
>
<!ELEMENT OPTION (%text; | ONEVENT)*>
<!ATTLIST OPTION
VALUE %vdata; #IMPLIED
TITLE %vdata; #IMPLIED
ONCLICK %URL; #IMPLIED
>
<!ELEMENT INPUT EMPTY>
<!ATTLIST INPUT
KEY NMTOKEN #REQUIRED
TYPE (TEXT|PASSWORD) 'TEXT'
VALUE %vdata; #IMPLIED
DEFAULT %vdata; #IMPLIED
FORMAT CDATA #IMPLIED
SIZE %number; #IMPLIED
MAXLENGTH %number; #IMPLIED
TABINDEX %number; #IMPLIED
TITLE %vdata; #IMPLIED
>
<!ELEMENT FIELDSET (%fields;)* >
<!ATTLIST FIELDSET
TITLE %vdata; #IMPLIED
>
<!--================ Choice elements ================-->
<!-- DEPRECATED -->
<!ELEMENT CE (%text;)*>
<!ATTLIST CE
VALUE %vdata; #IMPLIED
TASK %tasktypes; #IMPLIED
%taskattrs;
>
<!--================ Images ================-->
<!ENTITY % IAlign "(TOP|MIDDLE|BOTTOM)" >
<!ELEMENT IMG EMPTY>
<!ATTLIST IMG
ALT %vdata; #IMPLIED
SRC %URL; #IMPLIED
LOCALSRC %vdata; #IMPLIED
VSPACE %length; '0'
HSPACE %length; '0'
ALIGN %IAlign; 'BOTTOM'
HEIGHT %length; #IMPLIED
WIDTH %length; #IMPLIED
>
<!--================ Anchor ================-->
<!ELEMENT A (%inline;)*>
<!ATTLIST A
TITLE %vdata; #IMPLIED
%task;
>
<!--================ Text layout and line breaks ================-->
<!-- Text alignment attributes -->
<!ENTITY % TAlign "(LEFT|RIGHT|CENTER)" >
<!ELEMENT TAB EMPTY>
<!ATTLIST TAB
ALIGN %TAlign; 'LEFT'
>
<!ELEMENT EM (%flow;)*>
<!ELEMENT STRONG (%flow;)*>
<!ELEMENT B (%flow;)*>
<!ELEMENT I (%flow;)*>
<!ELEMENT U (%flow;)*>
<!ELEMENT BIG (%flow;)*>
<!ELEMENT SMALL (%flow;)*>
<!ENTITY % BRMode "(WRAP|NOWRAP)" >
<!ELEMENT BR EMPTY>
<!ATTLIST BR
ALIGN %TAlign; 'LEFT'
MODE %BRMode; #IMPLIED
>
<!ENTITY quot "&#34;"> <!-- quotation mark -->
<!ENTITY amp "&#38;#38;"> <!-- ampersand -->
<!ENTITY lt "&#38;#60;"> <!-- less than -->
<!ENTITY gt "&#62;"> <!-- greater than -->
<!ENTITY nbsp "&#160;"> <!-- non-breaking space -->
<!ENTITY shy "&#173;"> <!-- soft hyphen (discretionary hyphen) -->