Keep off the grass.  [electronic resource] 

 -  Nature  Jan 1969 
 - 205-6 p.  digital 
<br/><br/> Publication Type: Journal Article 
<br/><br/><label>ISSN: </label>0028-0836 
<br/><br/><label>Standard No.: </label>10.1038/221205a0  doi 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Cannabis<br/>Drug and Narcotic Control<br/>United Kingdom