@misc{indiciae3bffdb536867,
  title = {Sum rule practice.},
  author = {G van der Laan},
  year = {1999},
  doi = {10.1107/s0909049599000412},
  url = {https://pubmed.ncbi.nlm.nih.gov/15263426/},
  note = {Source identifier: 15263426}
}