Caiado, Rodrigo, Daniel Nascimento, Osvaldo Quelhas, Guilherme Tortorella, and Luis Rangel. “Towards Sustainability through Green, Lean and Six Sigma Integration at Service Industry: Review and Framework”. Technological and Economic Development of Economy 24, no. 4 (August 28, 2018): 1659-1678. Accessed December 2, 2024. https://aviation.vgtu.lt/index.php/TEDE/article/view/3119.