Chun-Nan Hung Lih-Hsing Hsu Ting-Yi Sung Christmas Tree: A Versatile 1-Fault-Tolerant Design for Token Rings. 55-63 1999 72 Inf. Process. Lett. 1-2 db/journals/ipl/ipl72.html#HungHS99 http://dx.doi.org/10.1016/S0020-0190(99)00122-2