@article{Petsche2010,
  author    = {Hans-Joachim Petsche},
  title     = {It began with Pestalozzi and Schleiermacher : Reflections on the polymath Hermann Grassmann (1809 - 1877)},
  url       = {http://www.ems-ph.org/journals/newsletter/pdf/2010-06-76.pdf},
  year      = {2010},
}