If you're interested in left-recursion in PEGS then, at the risk of gross immodesty, you may be interested in http://tratt.net/laurie/research/pubs/html/tratt__

If you're interested in left-recursion in PEGS then, at the risk of gross immodesty, you may be interested in http://tratt.net/laurie/research/pubs/html/tratt__direct_left_recursive_parsing_expression_grammars/ http://tratt.net/laurie/research/pubs/html/tratt__direct_lef... With less risk of immodesty you may also find http://arxiv.org/pdf/1207.0443.pdf?ref=driverlayer.com/web http://arxiv.org/pdf/1207.0443.pdf?ref=driverlayer.com/web interesting. There's probably more recent work than these two papers, but I'm a little out of date when it comes to the PEG world.