Leap year starting on Monday
A leap year starting on Monday is any year with 366 days (i.e. it includes 29 February) that begins on Monday, 1 January, and ends on Tuesday, 31 December. Its dominical letters hence are GF, such as the years 1912, 1940, 1968, 1996, 2024, 2052, 2080, and 2120 in the Gregorian calendar or, likewise, 2008, 2036, and 2064 in the obsolete Julian calendar. 
Any leap year that starts on Monday, Wednesday or Thursday has two Friday the 13ths. This leap year contains two Friday the 13ths in September and December. Common years starting on Tuesday share this characteristic.
Hanke–Henry Permanent Calendar
The key difference between Robert McClenon's calendar proposal and Henry's modification is that the former has a simple rule for determining which years have a leap week. This rule resembles the Gregorian leap year rule and has the same cycle length. Years whose numbers are divisible by 5 have a leap week, but years whose numbers are divisible by 40 do not have a leap week unless also divisible by 400. The main drawback of this rule is that the new year varies 17 days relative to the Gregorian new year (e.g. year 1965 begins 11 days earlier than Gregorian 1965 and year 2036 begins 6 days later than Gregorian 2036), whereas Henry's rule ensures that the new year always begins within three days of the Gregorian new year.