Kramer, M S <br/><br/>
Directionality, timing, and sample selection in epidemiologic research design.  [electronic resource] 

 -  Journal of clinical epidemiology  1989 
 - 827-8 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0895-4356 
<br/><br/><label>Standard No.: </label>10.1016/0895-4356(89)90094-2  doi 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Epidemiologic Methods<br/>Research Design<br/>Sampling Studies