I am told that Betty Meggers at the Smithsonian knows quite a bit about Tikal, as does George Stuart of the National Geographic Society. The address for Betty M. is the National Museum of Natural History, Room 310, MRC 112, SI, Wash. D.C. 20560. Telephone: 202 357 2674. The NGS is at 17th and M Sts. NW, Wash. D.C. 20005, Phone: 202 857 7000. Good Luck!