| http://www.eg3.com/8051.htm | Site with catalogs, softwares, tools and books list. |
| http://www.boerde.de/~matthias/m8051/ | Site with codes and programs. |
| http://www.intel.com | Site with 8051's datasheet and many tools (not all free!). |
| http://www.cefetsc.edu.br/vnoll/ | Site of professor Valdir Noll with a free tool (Register Compound) of 8051. |
| http://www.controller-br.com.br/ | Site with writers, emulatos. (not all free!). |
| http://www.8051.com/ | Site with toos and others things. |
| http://www.eel.ufsc.br/microprocessadores/ | Site about microcontrolers with option for download of Abacus - 8085's Simulator |