8333
The sample sets with printed stress concentrators were found to be statistically similar to their counterparts with milled stress concentrators .
 sample, stress, be, milled
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 sample, stress, be, milled