| http://www.w3.org/ns/prov#value | - The Robbins et al patent, supra, discloses a refrigerating package including an outer envelope formed of a suitable, flexible, fluid-tight sheet plastic material (for example polyethylene, vinyl or acetate), an inner envelope formed of the same material, a quantity of dry refrigerating chemical such as ammonium nitrate within the outer envelope and a quantity of water or other hydrous chemical dis
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