Best thing to do is go into a major retailer that sells bed linens and has them as opened displays to look at the labels on those. For the most part the ones I've seen have all the care, content, country of fabric origin, and country of completion on a tage that is sewn into a seam that sits at the foot of the bed. As with pillows and mattresses though many have the disclaimer about the tag being able to be removed by the consumer but still needing to be on for second-hand sale.
These links might help you:
Rules and Regulations Under the Textile Fiber Products Identification Act
http://www.ftc.gov/os/statutes/textile/rr-textl.shtmThreading Your Way Through the Labeling Requirements Under the Textile and Wool Acts
http://www.ftc.gov/bcp/edu/pubs/business/textile/bus21.shtmREGULATIONS UNDER SECTION 4 OF THE FAIR PACKAGING AND LABELING ACT
http://www.ftc.gov/os/statutes/fpla/part503.shtm