Economics of outdoor recreation 
by Marion Clawson and Jack L. Knetsch.  
 - Baltimore  Johns Hopkins Press for the Resources for the Future  cop. 1966.  
 - 328 s. 
<br/><br/><label>ISBN: </label>0801801214 (inb.) 0801813026 (hft.) 9780801801211 (inb.) 9780801813023 (hft.) 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Friluftsliv--Fèorenta staterna.