"" + ?
                      |
+ ?

                              |
                   +
                                      |
                                      |--
(.1917-18..1948) +     4 1942
                                      |-- (.. - )   
(1919)
                                      |-- "-"
(1920) + :
                                      |                                                     |
                                      |                                          
                                      |--
(1921)
                                      |--
(1921-1945) + :
                                      |                                            |
                                      |                                    (?)
                                      |-- ""
(1929)
                                      |-- ""
(1934)


Aerius 2002