Cita APA (7th ed.)

Helrich, K. (1984). Official methods of analysis of the Association of Official Analytical Chemists (14a. ed.). Association of Official Analytical Chemists.

Cita Chicago (17th ed.)

Helrich, Kenneth. Official Methods of Analysis of the Association of Official Analytical Chemists. 14a. ed. Arlington: Association of Official Analytical Chemists, 1984.

Cita MLA (9th ed.)

Helrich, Kenneth. Official Methods of Analysis of the Association of Official Analytical Chemists. 14a. ed. Association of Official Analytical Chemists, 1984.