Title: Dokladi na nauchno-prakticheska konferent︠s︡ii︠a︡ po usŭvŭrshenstvuvane brigadnata organizat︠s︡ii︠a︡ na truda i vnedri︠a︡vaneto na brigadnata stopanska smetka v minodobiva, metalurgii︠a︡ta, energetikata i geologii︠a︡ta
Subjects: Mineral industries, Power resources, Congresses, Geology
Places: Bulgaria