| First author | Year | Country | Probe frequency (MHz) | Numbera | Measurementsb | ONSDc (mm) |
| Lochner [16] | 2016 | Italy | 4 - 11 | 20 | 6 | 5.95 |
| Bauërle [12] | 2012 | Germany | 3 - 9 | 40 | 6 | 5.4 |
| Chen [23] | 2015 | China | 3 - 12 | 519 | 4 | 5.1 |
| Lefferts [24] | 2015 | USA | 7.5 - 10 | 20 | 6 | 4.99 |
| Blehar [21] | 2008 | USA | 8.5 | 27 | 4 | 4.3 |
| Kolade-yunusa [20] | 2017 | Nigeria | 7.5 | 150 | 4 | 4.20 |
| Our study | 2019 | Benin | 7.5 - 10 | 210 | 12 | 4.20 |
| Kim [15] | 2017 | South Korea | 3 - 11 | 585 | 6 | 4.11 |
| Shrestha [19] | 2016 | Nepal | 6 - 13 | 88 | 6 | 4.1 |
| Goeres [25] | 2016 | Canada | 6 - 13 | 120 | 4 | 3.68 |
| Wang [26] | 2016 | China | 3 - 9 | 230 | 16 | 3.46 |
| Ballantyne [11] | 2002 | Ukraine | 7 | 67 | 6 | 3.2 - 3.6 |