@online{CheckDigits,
title = {Check Digits},
abstract = {A decimal (or alphanumeric) digit added to a number for the purpose of detecting the sorts of errors humans typically make on data entry.},
url = {http://www.augustana.ualberta.ca/{\~{}}mohrj/algorithms/checkdigit.html},
year = 1999,
author = {Jonathan Mohr},
comment = {Notes about check digits, including Verhoeff's algorithm for a decimal check digit.},
urldate = {2022-01-18},
collections = {basically-computer-science,easily-explained,fun-maths-facts,unusual-arithmetic}
}