@misc{indiciae55de6345244b,
  title = {Preferred orientations in purine stacking.},
  author = {G K Helmkamp and N S Kondo},
  year = {1967},
  doi = {10.1016/0005-2787(67)90650-8},
  url = {https://pubmed.ncbi.nlm.nih.gov/6053243/},
  note = {Source identifier: 6053243}
}