@article{13159,
      author = {Gollin, D., and Evenson, Robert E. and ebrary, Inc.},
      url = {http://tind.wipo.int/record/13159},
      title = {Crop variety improvement and its effect on productivity :  the impact of international agricultural research /},
      recid = {13159},
      pages = {xxv, 522 pages :},
}