Loukas Georgiadis Haim Kaplan Nira Shafrir Robert Endre Tarjan Renato Fonseca F. Werneck Data structures for mergeable trees. 14 2011 7 ACM Transactions on Algorithms 2 http://doi.acm.org/10.1145/1921659.1921660 db/journals/talg/talg7.html#GeorgiadisKSTW11