Gregorian - Monday-based, week 53, 3 month
     December 2009             January 2010            February 2010     
   Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su     Mo Tu We Th Fr Sa Su
49     1  2  3  4  5  6  [7m53[27m              1  2  3   5  1  2  3  4  5  6  7
50  7  8  9 10 11 12 13   1  4  5  6  7  8  9 10   6  8  9 10 11 12 13 14
51 14 15 16 17 18 19 20   2 11 12 13 14 15 16 17   7 15 16 17 18 19 20 21
52 21 22 23 24 25 26 27   3 18 19 20 21 22 23 24   8 22 23 24 25 26 27 28
[7m53[27m 28 29 30 31            4 25 26 27 28 29 30 31