<!ELEMENT solar_planet (web_page_logo,planet*)>
<!ELEMENT web_page_logo (title1,title2)>
<!ELEMENT title1 (#PCDATA)>
<!ELEMENT title2 (#PCDATA)>
<!ELEMENT planet (picture,name,distance,physical_data,orbital_data,atmospheric_data,comment_label,comment_description,link)>
<!ELEMENT picture (#PCDATA)>
<!ATTLIST picture filename CDATA #REQUIRED>
<!ATTLIST picture x CDATA #REQUIRED>
<!ATTLIST picture y CDATA #REQUIRED>
<!ELEMENT name (#PCDATA)>
<!ELEMENT distance (#PCDATA)>
<!ELEMENT physical_data (physical_data_label,rlabel,radius,mlabel,mass,dlabel,density)>
<!ELEMENT physical_data_label (#PCDATA)>
<!ELEMENT rlabel (#PCDATA)>
<!ELEMENT radius (#PCDATA)>
<!ELEMENT mlabel (#PCDATA)>
<!ELEMENT mass (#PCDATA)>
<!ELEMENT dlabel (#PCDATA)>
<!ELEMENT density (#PCDATA)>
<!ELEMENT orbital_data (orbital_data_label,olabel,orbit,slabel,sidereal_period)>
<!ELEMENT orbital_data_label (#PCDATA)>
<!ELEMENT olabel (#PCDATA)>
<!ELEMENT orbit (#PCDATA)>
<!ELEMENT slabel (#PCDATA)>
<!ELEMENT sidereal_period (#PCDATA)>
<!ELEMENT atmospheric_data (atmospheric_data_label,clabel,composition,slabel,surface,tlabel,temperature)>
<!ELEMENT atmospheric_data_label (#PCDATA)>
<!ELEMENT clabel (#PCDATA)>
<!ELEMENT composition (#PCDATA)>
<!ELEMENT surface (#PCDATA)>
<!ELEMENT tlabel (#PCDATA)>
<!ELEMENT temperature (#PCDATA)>
<!ELEMENT comment_label (#PCDATA)>
<!ELEMENT comment_description (#PCDATA)>
<!ELEMENT link (#PCDATA)>