Here are some useful links about Scheme programming language:
in English
http://www.ccs.neu.edu/home/dorai/t-y-scheme/t-y-scheme-Z-H-1.html
http://www.r6rs.org/final/html/r6rs/r6rs-Z-H-2.html
and in Polish:
http://wazniak.mimuw.edu.pl/index.php?title=Programowanie_funkcyjne/Scheme
http://www.ds5.agh.edu.pl/~kubek2k/papers/gimp-scheme/scheme.html