| Keyword | Most frequent expressions (number of websites) |
|---|---|
| pp | vol pp (7), pe pp (5), pp pe (5), pp springer (3), euro pp (2), pp amsterdam (2), pp product (2), pp bag (2), quality pp (2), pp pdf (2), polypropylene pp (2), press pp (2), pp page (2) |
| ppe | equipment ppe (6), workwear ppe (6), ppe safety (2), ppe print (2), footwear ppe (2), medical ppe (2), ppe information (1), material ppe (1), ppe plastic (1), plastic ppe (1), ppe brass (1), glass ppe (1), ppe face (1) |