- P. Procházka, L. Smutka; Czech Republic as an Important Producer of Poppy Seed, Agris Online Papers in Economics and Informatics, Vol IV, No2, 2012
- A. D. Krikorian, M. C. Ledbetter. “Some Observations on the Cultivation of Opium Poppy (Papaver Somniferum L.) for Its Latex.” Botanical Review, vol. 41, no. 1, 1975, pp30–103
- A. Butterworth, Opium Wars, blog of the Royal Botanic Gardens, Kew, Sep 2015
- J. Halpern, D. Blistein; Opium: How an ancient flower shaped and poisoned our world, Hachette Books, 2019
- G. Samuelsson, Drugs of Natural Origin, Swedish Pharmaceutical Press 2005
- M. Robson, Opium: The Poisoned Poppy, FormAsia 1992
- E. Sevillano, Death Among Spain’s Poppy Fields, El Pais, 17th Aug 2017
See full list of Individual Species References.