@book{Lutz-PYW-2011,
 	author = {Lutz, Mark},
 	publisher = {Helion S.A.},
 	title = {Python. Wprowadzenie},
 	year =   2011 
 }
 
 @book{Gamma-IOW-2008
 	author = {Gamma, Erich and Helm, Richard and Johnson, Ralph and Vlissides,

John},

 	year = {2008},
 	title = {Inżynieria oprogramowania: Wzorce projektowe},
 	publisher = {WNT}
 }