@article{Gerhard2021,
  author    = {Reimund Gerhard},
  title     = {50 years of International Symposia on Electrets from 1967 to 2017},
  journal   = {IEEE electrical insulation magazine / Institute of Electrical and Electronics Engineers},
  series    = {a global history},
  volume    = {37},
  number    = {2},
  pages     = {50 -- 55},
  doi       = {10.1109/MEI.2021.9352710},
  year      = {2021},
}