UdG users
1969-04 Letter
1976-02-05 Letter
1976-03-07 Letter
1976-03-23 Letter
1976-06-08 Letter
1976-07-02 Letter
1976-07-15 Letter
1976-07-19 Letter
1976-11-05 Letter
1976-12-01 Letter
1976-12-12 Letter
[1977] Letter
1977-02-02 Letter
1977-02-28 Letter
1977-04-01 Letter
1977-04-15 Letter
1977-05-08 Letter
1977-07-08 Letter
1977-07-10 Letter
1977-08-18 Letter