@misc{indiciaed6c881810260,
  title = {What does productivity mean?},
  author = {William Hyman},
  doi = {10.2345/0899-8205(2004)38[492:wdpm]2.0.co;2},
  url = {https://pubmed.ncbi.nlm.nih.gov/15636000/},
  note = {Source identifier: 15636000}
}