@article{10_5427_jsing_2012_6e,
     author = {Tomonori Fukunaga},
     title = {Classification of curves on surfaces and free links via homotopy theory of words and phrases},
     journal = {Journal of Singularities},
     pages = {37--53},
     publisher = {mathdoc},
     volume = {6},
     year = {2012},
     doi = {10.5427/jsing.2012.6e},
     url = {http://geodesic.mathdoc.fr/articles/10.5427/jsing.2012.6e/}
}