Approaches to human geography. Los Angeles [u.a.] : SAGE, 2006. ix, 349 s. Available on Internet: <http://www.gbv.de/dms/goettingen/502206306.pdf> <http://www.loc.gov/catdir/enhancements/fy0661/2005930120-d.html> <http://www.loc.gov/catdir/enhancements/fy0661/2005930120-t.html> ISBN 978-0-7619-4263-4.