-
https://en.wikipedia.org/wiki/Cactus
- astrophytum.de
- cactiguide.com
- cactuscountry.com.au
- cactusmuseum.com
- the encyclopedia of cacti
- kaktus-kakteen-sukkulenten.de
- kaktusjunge.de
- lophophora.info
- lophophora-williamsii.de
- mesagarden.com
- plants of the world online
- sacredsucculents.com
- systematik der kakteengewächse
- the cactus and succulent society of america (CSSA)
- trichocereus.net
- tricholand.com
- tricho serious ethnobotany
- troutsnotes.com
