41
Published: 1978
42
Published: 1978
43
Published: 1988
Superior document: Enciklopedija Bălgarija 6
44
45
Published: 1982
Superior document: Enciklopedija Bălgarija 3
46
Published: 1978
Superior document: Enciklopedija Bălgarija 1
47
Published: 1958
48
“...Bălgarska akademija na naukite...”
49
“...Bălgarska akademija na naukite...”
50
Published: 1971
51
“...Bălgarska akademija na naukite...”
52
“...Bălgarska akademija na naukite...”
53
Published: [1998]-
54
Published: 1989
55
“...Bălgarska akademija na naukite...”
56
Published: 1972
57
“...Bălgarska akademija na naukite...”
58
“...Bălgarska akademija na naukite...”
59
“...Bălgarska akademija na naukite...”