1. Vasal SK. The quality protein maize story. Food and Nutrition Bulletin. 2000;21:445-450. DOI: 10.1177/156482650002100420
2. Kumar A, Jat SL, Kumar R, Yadav OP, Campus P. Maize Production Systems for Improving Resource-Use Efficiency and Livelihood Security. New Delhi: DMR; 2013. p. 123. Available from: https://s3.amazonaws.com/academia.edu.documents/44282018/Maize_production_systems_for_improving_r20160331-17801-1o7ae6u.pdf?response-content-disposition=inline%3B%20filename%3DMaize_production_systems_for_improving_r.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWOWYYGZ2Y53UL3A%2F20190806%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20190806T084645Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=5939035cb4b8292e04dc9ac5ec77d66af4be3e7f93ed3ad2e0da77d0710338bd
3. Vasal SK, Villegas E, Bjarnason M, Gelaw B, Goertz P. Genetic modifiers and breeding strategies in developing hard endosperm opaque-2 materials. In: Pollmer WG, Phillips RH, editors. Improvement of Quality Traits of Maize for Grain and Silage Use. London: Martinus Nijhoff; 1980. pp. 37-73. Available from: https://www.cabdirect.org/cabdirect/abstract/19811605259
4. Bjarnason M, Vasal SK. Breeding of quality protein maize (QPM). Plant Breeding Reviews. 1992;9:181-216 Available from: https://books.google.co.in/books?hl=en&lr=&id=W9aJNVA3C_0C&oi=fnd&pg=PA181&dq=Breeding+of+quality+protein+maize+(QPM)&ots=OJDw2JlGi8&sig=V5Hs2wgfklTUzXY5QmxlOCdyroo#v=onepage&q=Breeding%20of%20quality%20protein%20maize%20(QPM)&f=false
5. Villegas E, Vasal SK, Bjarnason M. Quality protein maize - what is it and how was it developed. In: Mertz ET, editor. Quality Protein Maize. St Paul, Minnesota: American Society Cereal Chemistry; 1992. pp. 27-48