Krug, E. E., & McGuigan, H. A. 1. (1951). An introduction to materia medica and pharmacology (Sixth edition.). Editorial Mosby Company.

Krug, E. Elsie, and Hugh Alister. 1866–1943 McGuigan. An Introduction to Materia Medica and Pharmacology. Sixth edition. Chicago: Editorial Mosby Company, 1951.

Krug, E. Elsie, and Hugh Alister. 1866–1943 McGuigan. An Introduction to Materia Medica and Pharmacology. Sixth edition. Editorial Mosby Company, 1951.