| year of publication | ISBN | author(s) | title |
|---|---|---|---|
| 1998 | 978-0-9534004-0-9 | Bruce Bayer | Haworthia Update: v. 2: Essays on Haworthia |
| 2001 | 978-0-9534004-1-6 | Harry Mays | Directory of Plants 1958-2001: Distributed by International Succulent Introductions with Alphabetical Index |
| 2002 | 978-0-9534004-2-3 | Ingo Breuer | Alsterworthia International: Special Issue No. I: An Haworthia Species Concept Update |
| 2003 | 978-0-9534004-3-0 | Lesley Milicich | Bulbinella in New Zealand |
| 2004 | 978-0-9534004-8-5 | Harry Mays | New Haworthia Species/ Combinations Published Subsequent to 'Haworthia Revisited': Pt. 1 |