http://www.history.com/topics/valentines-day/history-of-valentines-day
http://www.history.com/topics/valentines-day
http://online-english-lessons.eu/wordpress/2010/02/valentines-day-phrasal-verbs-idioms-and-sayings/
http://learnenglishteens.britishcouncil.org/uk-now/read-uk/valentines-day
St_Valentines_day (reading comprehension)