http://www.mif.pg.gda.pl/homepages/sylas/students/alg_podypl/w2.pdf
http://www.mif.pg.gda.pl/homepages/sylas/students/alg_podypl/w2.pdf
http://www.mif.pg.gda.pl/homepages/sylas/students/alg_podypl/w2.pdf
Click http://www.mif.pg.gda.pl/homepages/sylas/students/alg_podypl/w2.pdf link to open resource.