We have found 34 bags that match these dimensions.
47x32x20cm 18.5x12.5x8"
linear: 99cm/39" 18.8L
The bags below are not exactly the size you were looking for, but perhaps you'll come to like them.
47x26x14cm
36L
45x31x20cm
40x30x15cm
28L
39x29.5x20cm
44x32x18cm
~25L
47x30x18cm
46x30x20cm
25L
45x32x20cm
46x29x20cm 18x11.5x7"
linear: 95cm/36.5" 24L
39x25x20cm
23L
44x31x20cm
47x27x17cm
~22L
42x30x17cm
21L
42x30x15cm
42x30x18cm
linear: 90cm 20L
40x25x20cm
20L
19L
40x28x16cm
linear: 84cm 18L
40x23x20cm
18L
43x28x14.5cm
~17L
38x27x13cm
linear: 78cm 16L
40x32x15cm
16L
36x30x15cm
linear: 81cm 14L
36x31x13cm
14L
35x25x16cm
linear: 76cm 13L
39x28x12cm
13L
30x25x13cm
linear: 68cm 8L
28x19x15cm
~8L
29x20x13cm
linear: 62cm 7L
20x15x8cm
linear: 43cm 2.5L