@article {BertolaTovbisNLS2, title = {Universality for the focusing nonlinear Schr{\"o}dinger equation at the gradient catastrophe point: rational breathers and poles of the \it Tritronqu{\'e}e solution to Painlev{\'e} I}, journal = {Comm. Pure Appl. Math.}, volume = {66}, number = {5}, year = {2013}, pages = {678{\textendash}752}, issn = {0010-3640}, doi = {10.1002/cpa.21445}, url = {http://dx.doi.org/10.1002/cpa.21445}, author = {Marco Bertola and Alexander Tovbis} }