Which are the best paper on indexing and ranking?

Question

I'm reading a search engine source code without a document.

Are there classic papers on indexing and ranking?

Answer 1

You can read the original Google Paper: http://infolab.stanford.edu/~backrub/google.html

Answer 2

There is this excellent free online book on the subject, which covers indexing, queries, scoring, ranking, PageRank and everything else on the subject really. It's really very good. It covers the theory and practice of search engine technology and information retrieval. An essential read if you are diving into the nuts and bolts of a search engine, like Lucene.