https://www.youtube.com/watch?v=H0emIRXQXz4&list=PLD_h6icUlbphR2d9fsUDutseHqbzhwXzD&index=18
세미나
https://www.youtube.com/watch?v=NYQCViyb8P8&list=PLD_h6icUlbphR2d9fsUDutseHqbzhwXzD&index=20
