Outdoor swimming pool in Sliven Mineral Baths. In: D. N. Kochankov. Sliven Mineral Baths, Sofia: Медицина и физкултура, 1962, p. 14
Outdoor swimming pool in Sliven Mineral Baths. In: D. N. Kochankov. Sliven Mineral Baths, Sofia: Медицина и физкултура, 1962, p. 14