The obscured gallbladder.

@article{Bernstein2007TheOG,
  title={The obscured gallbladder.},
  author={Douglas Bernstein and Janet M Soeffing and Yassine J. Daoud and Joel M Fradin and Steven J. Kravet},
  journal={The American journal of medicine},
  year={2007},
  volume={120 8},
  pages={675-7}
}