UdG users
1960-01-04 Letter
1960-02-20 Letter
1960-02-24 Letter
1960-04-11 Letter
1961-06-29 Letter
1961-08-04 Letter
1963-05-03 Letter
1964-05-02 Letter
1964-05-21 Letter
1964-08-02 Letter
1966-03-22 Letter
1974-11-04 Letter
1975-09-27 Letter