Hummel Ruth · R. H. · R Hummel · Ruth S. Hummel
| title | ISBN-13 | year of publica- tion | other author(s) | |
|---|---|---|---|---|
| Gedanken zum Zeitalter des Wassermanns | 978-3-932539-13-8 | 1997 | ||
| Where Do Babies Come From? | 978-0-570-03553-4 | 1995 | Hummel Ruth | |
| Where Do Babies Come From? - Boys Edition - Learning About Sex | 978-0-7586-1410-0 | 2008 | ||
| Where Do Babies Come From: For Girls Ages 7-9 | 978-0-7586-1416-2 | 2008 | ||
| Where Do Babies Come From? - Learning About Sex | 978-0-570-03563-3 | 1998 | ||