+ * <informaltable frame="none"><tgroup cols="6"><tbody><row>
+ * <entry><mediaobject><imageobject><imagedata fileref="fig8a.png"/>
+ * </imageobject></mediaobject></entry>
+ * <entry><mediaobject><textobject><literallayout class="monospaced">
+ * A
+ * </literallayout></textobject></mediaobject></entry>
+ * <entry><mediaobject><imageobject><imagedata fileref="fig8b.png"/>
+ * </imageobject></mediaobject></entry>
+ * <entry><mediaobject><textobject><literallayout class="monospaced">
+ * O1
+ * / \
+ * A B
+ * </literallayout></textobject></mediaobject></entry>
+ * <entry><mediaobject><imageobject><imagedata fileref="fig8c.png"/>
+ * </imageobject></mediaobject></entry>
+ * <entry><mediaobject><textobject><literallayout class="monospaced">
+ * O1
+ * / \
+ * O2 B
+ * / \
+ * A C
+ * </literallayout></textobject></mediaobject></entry>
+ * </row></tbody></tgroup></informaltable>