1. Concentration of radon-222 in coal mines in England and Wales;Duggan;Nature,1968
2. Radon and its daughters in various British mines;Strong;Natl. Radiol. Prot. Board, Oxford, NRPB-R39,1975
3. Control of ventilation costs;Pearce;Colliery Guardian,1987
4. Controlled recirculation of air in the ventilation and cooling of a deep gold mine;Burton,1984
5. Application of controlled air recirculation to auxiliary ventilation systems and mine district ventilation circuits;Pickering,1984