00422nam a2200121Ia 4500008004100000040001700041082002400058100002300082245009700105260004000202300001500242650004300257190328s9999||||xx |||||||||||||| ||und||  aNITILcNITIL  221sta338.27bH496E  aHenderson, James E 4aThe efficiency of the coal industryban application of linear programmingcJames E Henderson  aCambridgebHarvard Universityc1958  axii, 140p.  aCoal trade; Coal mines and mining:coal