@article{oai:repository.dl.itc.u-tokyo.ac.jp:00000246,
 author = {Darwin, Horace},
 journal = {Seismological journal of Japan},
 month = {},
 note = {application/pdf},
 pages = {61--63},
 title = {A Bifilar Pendulum},
 volume = {19},
 year = {1894}
}