REGLACALCUL.COM REGLACALCUL.COM| Oughtred Society | The site of Oughtred Society |
| Photocalcul | The site of Gonzalo Martin : Very interesting and rich (French and Spanish) |
| Rod Lovett | Rod Lovett's website : lots of information |
| Nathan Zeldes' website | Very intersting and original |
| Slide rule museum | Very comprehensive website, lots of information |
| UKSRC | The website of the British Collectors Association | Dutch KRING website | Dutch Collectors Association (with an English version) | Valery Monnier's website | Calculating machines, fascinating about the arithmometer (French) |