1894
A large number of researchers began to associate specific AM constraints with their TO process , either as a TO process driver or a TO post-processor .
 manufacturing process: AM; concept or principle: process; material: as; concept or principle: process
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: 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:
 manufacturing process: AM; concept or principle: process; material: as; concept or principle: process