Download PTS Samyutta Nikaya Vol IV Electronic revised edition 2014 and Pali Metre by A.K. Warder 1967
Need to note down here before I forget. Updated May 2024: new PTS website 1. The Pali Metre by A.K. Warder (1967) https://palitextsociety.org/product/pali-metre/ 2. A revised edition of the Saṃyutta-nikāya, Volume IV, which includes variant readings found in other printed editions of the text. (Electronic revised edition 2014) find it in https://palitextsociety.org/corrections-and-additions/ You can also find others from this official PTS web page: https://palitextsociety.org/corrections-and-additions/ (Updated May 2024: this link is now invalid http://www.palitext.com/subpages/corrections.htm )