Hultgren Thor <br/><br/>
Railroad travel and the state of business 

 -  1943 
 - National bureau of economic research, occasional paper, 13 .
<br/><br/><label>Source: </label> General Book 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Business Cycle
<br/><br/><label>Dewey Class. No.: </label>X:740X4, H3