Asaduzzaman, M., Hasan, M. M., Hasan, M. M., Moniruzzaman, M. and Kabir Howlander, M. H. (2012) “Effect of bulb size and plant spacing on seed production of onion (Allium cepa L.)”, Bangladesh Journal of Agricultural Research, 37(3), pp. 405–414. doi: 10.3329/bjar.v37i3.12084.