Researchr is a web site for finding, collecting, sharing, and reviewing scientific publications, for researchers by researchers.
Sign up for an account to create a profile with publication list, tag and review your related work, and share bibliographies with your co-authors.
Holger Spakowski, Rahul Tripathi. Hierarchical Unambiguity. SIAM Journal on Computing, 38(5):2079-2112, 2009. [doi]