NEW YORK (Standard&Poor's) Sept. 4, 2008--Standard&Poor's Ratings Services raised its underlying rating (SPUR) two notches on Burton Elementary School District, Calif.'s certificates of participation (COPs) to 'A-' from 'BBB'. The outlook is stable. At the same time, Standard&Poor's assigned its 'A-' long-term rating, and stable outlook, to the district's 2008 COPs. "The upgrade is based on the district maintaining a good financial position with strong unreserved fund balances, as well as growth and diversification of the tax base," said Standard&Poor's credit analyst Timothy Barrett. The long-term and SPUR ratings reflect the district's general creditworthiness and covenant to budget and appropriate lease payments. The stable outlook reflects continued support from the state of