0000950134-99-003172 DEF 14A 1 19990525 19990422 AAON INC 0000824142 3585 870448736 NV 1231 DEF 14A 34 000-18953 99599045 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 DEF 14A 1 000095013499003172-001-seq1-def-14a.txt DEFINITIVE PROXY STATEMENT