PT  - JOURNAL ARTICLE
AU  - Claire Nicholl
TI  - Causal Relationships in Medicine—a Practical System for Critical Appraisal
AID  - 10.1136/jech.44.3.255-a
DP  - 1990 Sep 01
TA  - Journal of Epidemiology and Community Health
PG  - 255--255
VI  - 44
IP  - 3
4099  - http://jech.bmj.com/content/44/3/255.2.short
4100  - http://jech.bmj.com/content/44/3/255.2.full
SO  - J Epidemiol Community Health1990 Sep 01; 44