1. Marilyn Breen, ?A Krasnosel'skii Theorem for staircase paths in orthogonal polygons,?Journal of Geometry.
2. Marilyn Breen, lsAn intersection property for starshaped sets in the plane,?Geometriae Dedicata 37 (1991), 317?326.
3. Godfried Toussaint and Hossam El-Gindy, lsTraditional galleries are star-shaped if every two paintings are visible from some common point,? Technical Report SOCS- 81.10, McGill University, March 1981.