Wojciech Plandowski Wojciech Rytter Tomasz Szymacha Parallel Tree-Contraction and Fibonacci Numbers. 267-271 1996 59 Inf. Process. Lett. 5 db/journals/ipl/ipl59.html#PlandowskiRS96 http://dx.doi.org/10.1016/0020-0190(96)00118-4