Gypsum Association (USA)
Represents manufacturers of gypsum board in the U.S. and Canada and provides technical information and assistance to the construction industry and code enforcement community regarding gypsum board.
http://www.gypsum.org/

GP Gypsum Corporation
Gypsum at Georgia Pacific Building Products. High quality gypsum wallboards and gypsum drywall from one of North America’s leading gypsum board manufacturers.
http://www.gp.com/build/ProductGroup.aspx?pid=1064

DKT Co.,Ltd.
GreenCal, Agricultural Gypsum high purity gypsum. GreenCal is suitable for agricultural to improve soils structure with natural substances.
http://www.dktgypsum.com/

Gypsum Technologies Inc.
Canada. Offers engineering design, equipment supply, project and construction management, commissioning, and technical services for the gypsum wallboard manufacturing industry.
http://www.gypsumtechnologies.com

Berg's Rock Shop Rock
rock tumblers, Estwing rock hammers, and lapidary supplies,rockhounds,rockhound
http://www.bergsrockshop.com/

National Gypsum Company
A fully-integrated manufacturer and supplier of products and services used worldwide in building and construction, with primary emphasis on gold bond brand gypsum wallboard and joint treatment compounds.
http://www.nationalgypsum.com

Processed Gypsum Products Australia
Offers Gypsum which is 100% natural and will increases crop quality, yields and improve soil structure. Hi-Ag, Turf-Gyp, Micro-Gyp products benefit a wide range of agricultural enterprises.
http://www.pgp.com.au

Macedonian Rock Art Research Centre
The Center has discovered more than 460,000 rock drawings. Aims, history, activities, publications and personnel of the Center. Illustrated outline of rock art in Macedonia. World rock art congress in 2002.
http://www.unet.com.mk/rockart/

South Island Maori Rock Art Project
Focuses on the production of an archive resource on Rock Art taoka, along with supporting runanga in the conservation and interpretation of Rock Art sites.
http://www.ngaitahu.iwi.nz/dev-rockart.html

Utah Rock Art Research Association
Organization dedicated to the education about and preservation of Native American rock art. Annual symposium information, membership, publications, gallery of rock art.
http://www.utahrockart.org