* [Tryton](http://www.tryton.org/) - Free open source business solution. ([Demo](http://www.tryton.org/download.html), [Source Code](https://hg.tryton.org/)) `GPLv3``Python`
* [LedgerSMB](https://ledgersmb.org/) - The LedgerSMB project brings accounting software integrating invoicing, order processing, quotations and more (ERP) to small and midsize businesses. `GPLv2``Perl`