Anthony E. Richardson, Daniel R. Montello, and Mary Hegarty.
 <b>Spatial Knowledge Acquisition from Maps and from Navigation
  in Real and Virtual Environments</b>.
 <em>Memory and Cognition</em>, 27(4):741--750, 1999.
  <a href="http://vis.cs.brown.edu/docs/pdf/bib/g/Richardson-1999-SKA.pdf.html">(pdf)</a>
  <a href="http://vis.cs.brown.edu/results/bibtex/Richardson-1999-SKA.bib">(bibtex:
  Richardson-1999-SKA)</a>.