@misc{Kupka,
  author    = {Kupka, Friedrich},
  title     = {Interface with WP123200},
  subject      = {astrophysics},
  language  = {en}
}
@misc{Kupka,
  author    = {Kupka, Friedrich},
  title     = {A Turbulent Context},
  subject      = {astrophysics},
  language  = {en}
}