0000950134-99-004158 DEFA14A 1 19990514 AAON INC 0000824142 3585 870448736 NV 1231 DEFA14A 34 000-18953 99622130 900 PETROLEUM CLUB BUILDING 601 SOUTH BOULDER TULSA OK 74119-1300 9185832266 2425 SOUTH YUKON 2425 SOUTH YUKON TULSA OK 74107 DIAMOND HEAD RESOURCES INC 19900808 DEFA14A 1 000095013499004158-001-seq1-defa14a.txt DEFINITIVE PROXY - ADDITIONAL MATERIALS