Question

Is there any other case that must be fulfilled, apart from being perfectly divisible by 4, for a year to be a leap year?

Answer 1

yes

Answer 2

http://en.wikipedia.org/wiki/Leap_year#Algorithm

Funny how there's an algorithm in the wikipedia page to determine if a year is a leap year or not :-P

Answer 3

right above that is the description of the criteria for a leap year (divisible by 4 but not by 100 is a leap year, and divisible by 400 is a leap year)