Based on the Sandhi-splitter that Oliver Hellwig and me developed last year (https://github.com/OliverHellwig/sanskrit/blob/master/papers/2018emnlp/sandhi-rnn-hellwig-nehrdich.pdf), I have calculated approximate quotations and parallel passages within the GRETIL corpus. The HTML-tables of the quotations can be accessed here: http://buddhist-db.de/sanskrit-html/index.html

The tables are in a very simple format, but since links to the quoted passages are provided, it can be quite entertaining to navigate through the files and jump to the quoted passages.

The code and a small description of the used tools are on github: https://github.com/sebastian-nehrdich/gretil-quotations

The algorithm is based on fasttext vector representations of sequences with a fixed length of six tokens. This is short enough to match sets of two pādas of an anuṣṭubh stanza and long enough to avoid yielding too much unwanted results. I set the cutoff for the similarity intentionally low, so even matches which might be just very loosely related are included in the results. I think it is better to have some unrelated results from time to time than to miss something that might be of importance. Also the formatting of the GRETIL files is quite different from file to file, and it might have happened that during the process of extracting and splitting the Sanskrit sentences something did not go perfectly well. It is therefore always a good idea to check back with the original etext files. 

With best wishes, 

Sebastian Nehrdich