http://www.agendaweb.org/grammar/there-is-there-are/index.html
http://www.adelescorner.org/grammar/there_is/thereis.html
http://www.montsemorales.com/gramatica/thereisare.htm
http://www.carmenlu.com/first/grammar/thereis1_2.htm
http://www.montsemorales.com/gramatica/thereis2.htm
http://s.mound.free.fr/skyblues67/fridges_some-any/fridges1.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=1274
http://www.englishexercises.org/makeagame/viewgame.asp?id=2920