nikolai kardashev - on the inevitability and the possible structures of supercivilizations
TRANSCRIPT
1985IAUS..112..497K
1985IAUS..112..497K
1985IAUS..112..497K
1985IAUS..112..497K
1985IAUS..112..497K
1985IAUS..112..497K
1985IAUS..112..497K
1985IAUS..112..497K