Keen, Linda. "COLLARS ON RIEMANN SURFACES".
Discontinuous Groups and Riemann Surfaces (AM-79), Volume 79: Proceedings of the 1973 Conference at the University of Maryland. (AM-79), edited by Leon Greenberg, Princeton: Princeton University Press, 2016, pp. 263-268.
https://doi.org/10.1515/9781400881642-021Keen, L. (2016). COLLARS ON RIEMANN SURFACES. In L. Greenberg (Ed.),
Discontinuous Groups and Riemann Surfaces (AM-79), Volume 79: Proceedings of the 1973 Conference at the University of Maryland. (AM-79) (pp. 263-268). Princeton: Princeton University Press.
https://doi.org/10.1515/9781400881642-021Keen, L. 2016. COLLARS ON RIEMANN SURFACES. In: Greenberg, L. ed.
Discontinuous Groups and Riemann Surfaces (AM-79), Volume 79: Proceedings of the 1973 Conference at the University of Maryland. (AM-79). Princeton: Princeton University Press, pp. 263-268.
https://doi.org/10.1515/9781400881642-021Keen, Linda. "COLLARS ON RIEMANN SURFACES" In
Discontinuous Groups and Riemann Surfaces (AM-79), Volume 79: Proceedings of the 1973 Conference at the University of Maryland. (AM-79) edited by Leon Greenberg, 263-268. Princeton: Princeton University Press, 2016.
https://doi.org/10.1515/9781400881642-021Keen L. COLLARS ON RIEMANN SURFACES. In: Greenberg L (ed.)
Discontinuous Groups and Riemann Surfaces (AM-79), Volume 79: Proceedings of the 1973 Conference at the University of Maryland. (AM-79). Princeton: Princeton University Press; 2016. p.263-268.
https://doi.org/10.1515/9781400881642-021