APA (7th ed.) Citation

Sigel, A., & Sigel, H. (1999). Interrelations between free radicals and metal ions in life processes. Metal ions in biological systems.

Chicago Style (17th ed.) Citation

Sigel, Astrid, and Helmut Sigel. "Interrelations Between Free Radicals and Metal Ions in Life Processes." Metal Ions in Biological Systems 1999.

MLA (9th ed.) Citation

Sigel, Astrid, and Helmut Sigel. "Interrelations Between Free Radicals and Metal Ions in Life Processes." Metal Ions in Biological Systems, 1999.

Warning: These citations may not always be 100% accurate.