Sigma Chemical Company : Biochemical and organic compounds for research and diagnostic clinical reagents.

MLA

Sigma Chemical Company : Biochemical and Organic Compounds for Research and Diagnostic Clinical Reagents. St. Louis, 1988.

APA

(1988). Sigma Chemical Company : Biochemical and organic compounds for research and diagnostic clinical reagents. St. Louis.

Chicago

Sigma Chemical Company : Biochemical and Organic Compounds for Research and Diagnostic Clinical Reagents. St. Louis, 1988.