1.
Atanasov A, Kaloyanov T. Methodological Approaches of Sampling Surveys for Examining the Beneficiaries of OP HRD 2014-2020. НТ [Internet]. 2017 Dec. 21 [cited 2026 Jul. 22];(2):27-59. Available from: https://bjiep.e-dnrs.org/index.php/rp/article/view/5611