Choi H. S., Byun J. M., Lee W. S., Bang S. R., Kim Y. D. (2016). "Research trend of
additive manufacturing technology - A= B+C+D+E, add innovative concept to current
additive manufacturing technology: Four conceptual factors for building additive manufacturing
technology -", Journal of Powder Materials, Vol. 23, No. 2, pp. 149-169 (in Korean).