| EditableSModel | Model deemed for editing. | 
| SModel | Represents a model. | 
| SModel.Problem | Represents a problem with the persistence. | 
| SModelId | Uniquely identifies a model within a module. | 
| SModelListener | This interface can be implemented to track model state. | 
| SModelReference | Represents a unique reference to a model, which remains valid across subsequent read and write actions. | 
| SModelScope |  | 
| SNode | NODE STATES
 A node can have 2 states: it can be either attached to some repository or not. | 
| SNodeAccessListener | PROVISIONAL API. | 
| SNodeChangeListener | Listener to track changes to individual nodes in a model. | 
| SNodeId | Uniquely identifies a node within a model. | 
| SNodeReference | Represents a unique global reference to a node. | 
| SReference | Represents reference between nodes. |