Gomez-Larranaga, J. C., Gonzalez-Acuna, F., & Heil, W. (no date). Models Of Simply-connected Trivalent 2-dimensional Stratifolds. Boletin De La Sociedad Matematica Mexicana. Retrieved from https://purl.lib.fsu.edu/diginole/FSU_libsubv1_wos_000522901500001