public static string[] MonthsInQuarter(DateTime dateTime)
{
int quarter = (dateTime.Month + 2) / 3;
DateTime tmp = dateTime.AddMonths(-(dateTime.Month - 1));
tmp = tmp.AddMonths((3 * quarter) - 3);
return new[]
{
string.Format("{0:yyyyMM}", tmp),
string.Format("{0:yyyyMM}", tmp.AddMonths(1)),
string.Format("{0:yyyyMM}", tmp.AddMonths(2))
};
}