Narodna︠i︡a Respublika Bolgari︠i︡a : voprosy stroitelʹstva razvitogo so︠t︡sialisticheskogo obshchestva : sbornik stateĭ - La︠t︡sis, O. R. (Otto Rudolʹfovich); Shabunina, V. I. (Akademi︠i︡a nauk SSSR, In-t ėkonomiki mirovoĭ so︠t︡sialisticheskoĭ sistemy, 1985)