Cita APA

Helrich, K. E. (1990). Official methods of analysis of the Association of Official Analytical Chemists (15th ed.).

Chicago Edition Citation

Helrich, Kenneth; Editor. Official Methods of Analysis of the Association of Official Analytical Chemists. 15th ed. Virginia, Association of Official Analytical Chemists, 1990.

Cita MLA

Helrich, Kenneth; Editor. Official Methods of Analysis of the Association of Official Analytical Chemists. 15th ed. 1990.