Tantiphanwadi, P., Siripanya, A. , Panyakunanont, P. , Thanachotanankul, P. , Wongpatiwate, N. , Phwngmalay, S. and Waiyanit, S. 2020. Production Improvement Steps: Lean, Six Sigma and Lean Automation. Naresuan University Engineering Journal. 15, 2 (Dec. 2020), 47–64.