Class Diagram

                                      n .. 1
  +-----------------------------------------------------------------------------+
  v                                                                             v
+------------+   n .. 1   +--------------+   n .. m   +----------+   n .. m   +--------------+
|    Note    | <--------> |              | <--------> | Labeling | <--------> |    Label     |
+------------+            |              |            +----------+            +--------------+
                          |              |                                      ^          ^
                          |   Concept    |                                      +----------+
                          |              |                                        relation
+------------+   n .. m   |              |   1 .. n   +----------+
| Collection | <--------> |              | <--------> |  Match   |
+------------+            +--------------+            +----------+
  ^        ^                ^          ^
  +--------+                +----------+
    n .. m                    relation

(generated with graph-easy from Class Diagram)

Note that this diagram only provides a high-level overview; for each class presented here there are sub-classes implementing specific behavior.