@article{article288413b2,
title   = {Topology of simple singularities of ruled surfaces in 'R POT. P'},
author = {Barbosa, Grazielle Feliciani and Martins, Rodrigo and Saia, Marcelo José},
year = {2012},
doi = {10.1016/j.topol.2011.09.013},
journal   = {Topology and its Applications}
}