By Ingo Wegener (SIAM, 2000). Errata, solutions to exercises, updates on open problems.

By P. Crescenzi and V. Kann; KTH Stockholm. A continuously updated version of the appendix from the book "Complexity and Approximation" (Springer, 1999).

By Heribert Vollmer (Springer, 1999). Excerpts, errata, bibliography in BibTeX format.

Michael Sipser (PWS Publishing) Table of contents, errata.

A downloadable textbook by Herbert S. Wilf. Each chapter is available as compressed PostScript or PDF.

By Donald E. Knuth. Bibliographic details of the published volumes (1-3, various editions and translations) and on-line beta versions of parts of volume 4, "Combinatorial Algorithms".

A web text by Bruno R. Preiss of the University of Waterloo.

By Gaston H. Gonnet and Ricardo Baeza-Yates. The preface, table of contents, index and all source code of this handbook. The main goal is to make available through Internet the source code of many algorithms (in C and/or Pascal) that have been already tested.