[MIDAS로 배우는 구조역학] 7장 스프링 해석 Spring
• YouTube: 
https://www.youtube.com/watch?v=979AeGkN0NE&list=PLXMmPDu5-PnfaY2KqGNHYeIbZ4AMntpO1&index=7
• PDF: 
https://www.dropbox.com/s/5nbf1py34hiwpdr/04_07%20Spring.pdf?dl=0