Ramanathan, 1946; Collins, Fan, 1954; Sutherland, Blackwell, Simeral, 1954; Lax, Burstein, 1955; Clark, Ditchburn, Dyer, 1956; Stephen, 1958; Kaiser, Bond, 1959; Elliott, 1960; , 1966; ., 1964, 1965, 1966, 19681,2; 19691,2 .).

, , , (. 67 68).

. , .

3-6 (2030, 2450 3200 -1), , .

. (Kaiser, Bond, 1959) , 480, 1100, 1220 1280 -1. 1280 -1 (7,8 ) : N = 5,8 1018 128