graph <id=ID>
    + point <x, y> [2..2]
    |
    + legend <width>
    |   + point <x,y>
    |
    + axis <id=ID, min=double, max=double, visibility={none|min|max|both}, [autoscale=boolean], [rotate-text=boolean]> [2..2]
    |   + tick-metric <number=integer, subticks=boolean, size=double, line-width=double>
    |   + scale-metric <font={fontType}, size=double, type={logarithmic|linear|date} >
    |   + grid <id=ID, [show=boolean], [highlight-zero=boolean]>
    |      + regular-stroke-ref | regular-stroke <strokeStyleType>
    |      + zero-stroke-ref | zero-stroke <strokeStyleType>
    |
    + caption <id=ID, font={fontType}, font-size=double, position={alignmentType}, distance=double, [line-skip=double]> [1..*]
    |   + simple-text | rich-text
    |
    + dataset <id=ID, url=string, graph-style={graphStyleType}, point-symbol={pointSymbolType}> [0..*]
        + stroke | stroke-ref