APA (7th ed.) Citation
British Drug Houses, ltd., London, & Hopkin and Williams, ltd., London. (1949). 'Analar' standards for laboratory chemicals: Being improved standards for the analytical reagents formerly known as 'A. R.' (4ta. ed. Formulated and issued jointly by the British Drug Houses, ltd. and Hopkin & Williams, ltd.).
Chicago Style (17th ed.) Citation
British Drug Houses, ltd., London, and ltd. Hopkin and Williams. 'Analar' Standards for Laboratory Chemicals: Being Improved Standards for the Analytical Reagents Formerly Known as 'A. R.'. 4ta. ed. Formulated and issued jointly by the British Drug Houses, ltd. and Hopkin & Williams, ltd. London, 1949.
MLA (9th ed.) Citation
British Drug Houses, ltd., London, and ltd. Hopkin and Williams. 'Analar' Standards for Laboratory Chemicals: Being Improved Standards for the Analytical Reagents Formerly Known as 'A. R.'. 4ta. ed. Formulated and issued jointly by the British Drug Houses, ltd. and Hopkin & Williams, ltd. 1949.
Warning: These citations may not always be 100% accurate.