APA Style

Helrich, Kenneth. (1990). Official Methods of Analysis of The Association of Official Analytical Chemists (15th.ed). Virginia: Association of Official Analytical Chemists.

Chicago Style

Helrich, Kenneth. Official Methods of Analysis of The Association of Official Analytical Chemists. 15th.ed Virginia: Association of Official Analytical Chemists, 1990. Textbook.

MLA Style

Helrich, Kenneth. Official Methods of Analysis of The Association of Official Analytical Chemists. 15th.ed Virginia: Association of Official Analytical Chemists, 1990. Textbook.

Turabian Style

Helrich, Kenneth. Official Methods of Analysis of The Association of Official Analytical Chemists. 15th.ed Virginia: Association of Official Analytical Chemists, 1990. Textbook.