1. Berardinelli, A., Berman, L.W.: Systematic celestial configurations. Ars Math. Contemp., 7(2), (2014)
2. Berman, L.W.: A characterization of astral (n 4) configurations. Discret. Comput. Geom. 26(4), 603–612 (2001)
3. Berman, L.W.: Even astral configurations. Electron. J. Comb. 11(1), Research Paper 37, 23 (2004). (electronic)
4. Berman, L.W.: Movable (n 4) configurations. Electron. J. Comb. 13(1), Research Paper 104, 30 (2006). (electronic)
5. Berman, L.W.: Some results on odd astral configurations. Electron. J. Comb. 13(1), Research Paper 27, 31 (2006). (electronic)