| year of publication | ISBN | author(s) | title |
|---|---|---|---|
| 2007 | 978-1-933941-08-0 | Robert Duncan | Robert Duncan Simple Things 2008 Calendar |
| 2014 | 978-1-933941-40-0 | Inc. Robert Duncan Studios | 2015 Robert Duncan "Simple Things" |
| 2015 | 978-1-933941-44-8 | Robert Duncan | 2016 Robert Duncan Simple Things Deluxe Wall Calendar |
| 2017 | 978-1-933941-50-9 | '' | 2018 Robert Duncan Simple Things Deluxe Wall Calendar |
| 2019 | 978-1-933941-58-5 | '' | 2020 Robert Duncan "Simple Things Deluxe Wall Calendar |