1. Control of other symptoms;Baines,1978
2. Palliative symptom control;Doyle,1984
3. Cough and other respiratory reflexes;Korpas,1979
4. Reflex control of breathing;Widdicombe,1974
5. Codeine and its alternatives for pain and cough relief. The antitussive action of codeine-mechanism, methodology and evaluation;Eddy;Bull WHO,1969