Latest DTD for the XML data file:

<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT ch_st EMPTY>
<!ATTLIST ch_st
    chst_ref IDREF #REQUIRED
>
<!ELEMENT char EMPTY>
<!ATTLIST char
    ch_ref IDREF #REQUIRED
>
<!ELEMENT character EMPTY>
<!ATTLIST character
    ch_id ID #REQUIRED
>
<!ELEMENT character_state (char+, text+, image*)>
<!ATTLIST character_state
    chst_id ID #REQUIRED
    difficulty (difficult | medium | easy) #REQUIRED
>
<!ELEMENT description (text+, ch_st+, image*)>
<!ATTLIST description
    desc_id ID #REQUIRED
>
<!ELEMENT image EMPTY>
<!ATTLIST image
    src CDATA #REQUIRED
>
<!ELEMENT inuit_data (character*, character_state*, taxa*)>
<!ATTLIST inuit_data
    authority CDATA #REQUIRED
    master (N | Y) #REQUIRED
    master_url CDATA #IMPLIED
>
<!ELEMENT taxa (description+)>
<!ATTLIST taxa
    name ID #REQUIRED
>
<!ELEMENT text (#PCDATA)>
<!ATTLIST text
    lang CDATA #IMPLIED
>
<!ELEMENT xml (inuit_data?)>