@article{10_4064_fm232_1_7,
     author = {Yin Tian},
     title = {A categorification of the square root of $-1$},
     journal = {Fundamenta Mathematicae},
     pages = {89--98},
     publisher = {mathdoc},
     volume = {232},
     number = {1},
     year = {2016},
     doi = {10.4064/fm232-1-7},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm232-1-7/}
}