@misc{indiciae1556bcd46182,
  title = {Differential Calculus in Linear Topological Spaces.},
  author = {A D Michal},
  year = {1938},
  doi = {10.1073/pnas.24.8.340},
  url = {https://pubmed.ncbi.nlm.nih.gov/16588235/},
  note = {Source identifier: 16588235}
}