21
22
Publicado 1971
“...E.U.A . National Bureau of Standards...”
23
24
25
26
27
28
29
30
Publicado 1977
“...E.U.A . National Bureau of Standards...”
31
32
33
34
35
36
37
Publicado 1969
“...E.U.A . National Bureau of Standards...”
38
39
40