1. The Collins paperback English Dictionary 2nd Edition. Harper Collins. Glasgow: 1991.
2. Hannay DR. Symptom prevalence in the community.J R Coll Gen Pract 1978; 28: 492–9.
3. Ridsdale L. Tired all the time.BMJ 1991; 303: 1490–1.
4. Morrell DC. Symptom interpretation in general practice.J R Coll Gen Pract 1972; 22: 295–309.
5. Jerrett WA. Lethargy in general practice. The Practitioner 1981; 4: 731–7.