How to make acetate-acetic acid buffer solutions

Sodium acetate-acetic acid buffer solutions, pH 3.7-5.6

Sodium acetate trihydrate, CH3COONa.3H2O, M.Wt. 136.09;
0.2M solution contains 27.22g/l.
Acetic acid, glacial is ~17.47M.

x ml 0.2M NaOAc and y ml 0.2M HOAc mixed.

pH, 18°C X mL

0.2M NaOAc

Y mL

0.2M HOAc
3.7 10.0 90.0
3.8 12.0 88.0
4.0 18.0 82.0
4.2 26.5 73.5
4.4 37.0 63.0
4.6 49.0 51.0
4.8 59.0 41.0
5.0 70.0 30.0
5.2 79.0 21.0
5.4 86.0 14.0
5.6 91.0 9.0