@article{AIF_2012__62_1_77_0,
     author = {Ishida, Tomohiko},
     title = {Second cohomology classes of the group of $C^1$-flat diffeomorphisms},
     journal = {Annales de l'Institut Fourier},
     pages = {77--85},
     publisher = {Association des Annales de l{\textquoteright}institut Fourier},
     volume = {62},
     number = {1},
     year = {2012},
     doi = {10.5802/aif.2699},
     mrnumber = {2986265},
     zbl = {1253.58007},
     language = {en},
     url = {https://aif.centre-mersenne.org/articles/10.5802/aif.2699/}
}