http://s.mound.free.fr/skyblues67/fridges_some-any/some-anyeasy-1.htm
http://www.englisch-hilfen.de/en/exercises/confusing_words/some_any.htm
http://www.agendaweb.org/exercises/grammar/any-some-4
http://www.helpforenglish.cz/article/2006062602-some-any-no