1 digraph ReferredGroup {

     2   mindist = 2.0

     3   1 -> 3 [label="choice"]

     4   1 -> 3 [label="all"]

     5   1 -> 2 [label="annotation"]

     6   1 -> 3 [label="sequence"]

     7   2 -> 3 [label="choice"]

     8   2 -> 3 [label="all"]

     9   2 -> 3 [label="sequence"]

    10   1 [shape=doublecircle, style=filled, color=blue]

    11   2 [shape=doublecircle, style=filled, color=green]

    12   3 [shape=doublecircle, style=filled, color=green]

    13 }