@misc{gfp_group_universal_cover_sl_2_r,
  author = {{Groups for Physics}},
  title = {Universal cover of SL(2, R)},
  howpublished = {Groups for Physics reference},
  url = {https://groups.qft.org/atlas/groups/universal-cover-sl-2-r/},
  version = {2026.11-workbench.4},
  note = {Research workbench IV; review status recorded on canonical page}
}