Si clauses
www.grammar.spanishintexas.org/verbs/si-clauses/
www.elearnspanishlanguage.com/grammar/siclauses.html
http://users.ipfw.edu/jehle/courses/condic.htm
https://mediagallery.peddie.org/gs/handler/getmedia.ashx?moid=325&dt=2&g=1
http://www.orbilat.com/Languages/French/Grammar/Syntax/Clauses/French-Syntax-Clauses-Si.html
http://www.bowdoin.edu/~eyepes/newgr/ats/52.htm
http://www.quia.com/quiz/677500.html
http://doncarlos123.tripod.com/subjinsiclauses.html
http://www.learnspanishfeelgood.com/spanish-if-clauses-conditional3.html
http://www.123teachme.com/learn_spanish/forming_if_clauses
http://www.quia.com/quiz/648667.html