@misc{indiciae21574c7b2568,
  title = {Visually perceived vertical and visually perceived horizontal are not orthogonal.},
  author = {G A Betts and I S Curthoys},
  year = {1998},
  doi = {10.1016/s0042-6989(97)00401-x},
  url = {https://pubmed.ncbi.nlm.nih.gov/9797945/},
  note = {Source identifier: 9797945}
}