@article{walker_1836, 
  title={Computations of the principal phases of the solar eclipse of May 15th, 1836, for several places in the United States}, 
  volume={21}, 
  DOI={10.1016/s0016-0032(36)91146-8}, 
  publisher={Elsevier BV}, 
  author={Walker}, 
  year={1836}
  }