@article{oai:repository.dl.itc.u-tokyo.ac.jp:00037772,
 author = {Yoshiye, T.},
 journal = {Journal of the College of Science, Imperial University of Tokyo},
 month = {Aug},
 pages = {1--18},
 title = {Ueber die charakteristische Mannigfaltigkeit der partiellen Differentialgleichungen erster Ordnung},
 volume = {32},
 year = {1913}
}