Liam Roditty, Uri Zwick. Replacement Paths and ::::k:::: Simple Shortest Paths in Unweighted Directed Graphs. In Luís Caires, Giuseppe F. Italiano, Luís Monteiro, Catuscia Palamidessi, Moti Yung, editors, Automata, Languages and Programming, 32nd International Colloquium, ICALP 2005, Lisbon, Portugal, July 11-15, 2005, Proceedings. Volume 3580 of Lecture Notes in Computer Science, pages 249-260, Springer, 2005. [doi]