         super.init()
         _id=String(decoder.decodeObjectOfClass( NSString.self, forKey:Default.UID_KEY)! as NSString? )
         referenceName=String(decoder.decodeObjectOfClass( NSString.self, forKey:Default.REFERENCE_NAME_KEY)! as NSString?)
+        Registry.register(self)//registration on deserialization
     }
     
     public class func supportsSecureCoding() -> Bool{

    
    // The id is always  created locally
    // and used as primary index by MONGODB
    internal var _id:String=Default.NO_UID
    
    private var _referenceName:String=Default.NO_NAME
    

    
    // MARK: -
    
    private func _createUIDifNecessary(){
        if _id==Default.NO_UID{
            _id=Bartleby.createUID()
            Registry.register(self) // register on creation
