@ARTICLE {, title = {The role of the protractor in understanding the universe}, author = {Křížek, Michal}, journal = {Obzory matematiky, fyziky a informatiky}, year = {2008}, volume = {37}, number = {1}, pages = {36--47}, issn = {1335-4981}, abstract = {We present several examples to show how such an ordinary and simple instrument as the usual protractor helped to create the modern view of the universe.}, }