UdG users
1955-09-23 Letter
1955-10-17 Letter
1959-03-22 Letter
1960-02-22 Letter
1960-03-20 Letter
1960-03-21 Letter
1961-11-23 Letter
1962-03-01 Letter
1970-11-11 Letter
1973-05-24 Letter
1977-12-10 Letter