NR 660.11(8)(k)(k) 40 CFR part 60, Appendix A, Method 3A, Determination of Oxygen and Carbon Dioxide Concentrations in Emissions from Stationary Sources (Instrumental Analyzer Procedure), incorporated by reference for ch. NR 666 Appendix IX. NR 660.11(9)(9) The 1987 Standard Industrial Classification (SIC) is available from the Occupational Safety and Health Administration, 200 Constitution Ave NW, Washington, DC 20210, (800) 321-6742, www.osha.gov, incorporated by reference for ss. NR 661.0003 (3), 661.0004 (1), 661.0032, 668.40, 670.013 (3), and 679.01 (8).