Grammar Referance
Name: Theodore Email: thsiaf1@hotmail.gr
has shared the following links to learn Sanskrit…
As far as I can understand, this is mostly a public domain site with electronic libraries. Books are free to download, but they are not copyrighted because most of them date from the end of the last century or earlier and are quite large in terms of megabytes.
These are mostly good quality scans converted to PDF, although many are also in formats suitable for e-readers like Kindle and ePub, although they don’t convert very well on my Sony e-reader, at least. So I recommend PDF.

