These 2 wikitextbooks are from England. Created by teachers and student moderators. GCSE stands for General Certificate of Secondary Education. Pupils in England typically take 9 or 10 of these exams when they are 16, then specialise down to 3 or 4 A-levels up to the end of High School. So a whole GCSE course is between 120 and 150 hours of study in total.

for 15-16 yrs olds
http://www.wikitextbook.co.uk/index.php/Category:GCSE_Business_Studies

for 17-18 yrs olds
http://www.wikitextbook.co.uk/index.php/Category:A_level_Business_Studies

Business Studies Encylopedia
http://courses.chalkface.com/public_html/encyc/Indexm.html