Locklin, David Philip,  1897- <br/><br/>
Economics of transportation / 
by D. Philip Locklin 
 - 6th ed. 
 - Homewood, Ill. :  R. D. Irwin,  1966 
 - xii, 882 p. :  ill. ;  24 cm. 
<br/><br/>Includes bibliographical references 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Transportation--United States<br/>Railroads--United States