((element "bikes" "-" "-" (zero-or-more "bike") "") (element "bike" "-" "-" "(frame, wheel+, brake*, lock*)" "") (element "frame" "-" "-" "EMPTY" "") (element "wheel" "-" "-" "EMPTY" "") (element "brake" "-" "-" "EMPTY" "") (element "lock" "-" "-" "EMPTY" "") (attribute "bikes" ()) (attribute "bike" (("kind" ("mountain-bike, racer-bike, tourist-bike, other") "tourist-bike"))) (attribute "frame" (("frame-number" "CDATA" "#REQUIRED"))) (attribute "wheel" (("size" "CDATA" "#REQUIRED") ("tube-kind" "CDATA" "#IMPLIED"))) (attribute "brake" (("kind" "CDATA" "#IMPLIED") ("brand" "CDATA" "#IMPLIED"))) (attribute "lock" (("brand" "CDATA" "#IMPLIED") ("insurance-approved" ("true" "false") "#REQUIRED"))) (entity "Number" "CDATA") (entity "Boolean" "(true | false)"))