21
22
23
24
25
26
27
Date [[s.a.]]
“...
Bulgarije
...”
monografie
28
29
30
31
32
Memorandum van de Union Centrale Coopérative
Date 1969
“...
Bulgarije
...”
brochure
33
“...
Bulgarije
...”
monografie
34
35
36
“...
Bulgarije
...”
monografie
37
38
39
40
Date 1985
“...
Bulgarije
...”
brochure