@misc{indiciaeb9bbe6af619a,
  title = {Task difficulty and the frustration effect.},
  author = {R R Schmeck and J L Bruning},
  year = {1968},
  doi = {10.1037/h0026476},
  url = {https://pubmed.ncbi.nlm.nih.gov/5705860/},
  note = {Source identifier: 5705860}
}