@inproceedings{sergei2003duality,
  title={Duality and Fibrations on G_2 Manifolds},
  author={Sergei Gukov, Shing-Tung Yau, and Eric Zaslow},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224203744084488080},
  booktitle={Turkish Journal of Mathematics},
  volume={27},
  number={1},
  pages={61-98},
  year={2003},
}
             
            
                
Sergei Gukov, Shing-Tung Yau, and Eric Zaslow. Duality and Fibrations on G_2 Manifolds. 2003. Vol. 27. In Turkish Journal of Mathematics. pp.61-98. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224203744084488080.