Verstraete B, Moon HK, Smets E, Huysmans S (2014). "Orbicules in flowering plants: a phylogenetic perspective on their form and function". The Botanical Review. 80 (2): 107–134. doi:10.1007/s12229-014-9135-1. S2CID255562584.
Christensen JE, Horner Jr HT, Lersten NR (1972). "Pollen wall and tapetal orbicular wall development in Sorghum bicolor (Gramineae)". American Journal of Botany. 59 (1): 43–58. doi:10.2307/2441229. JSTOR2441229.
Furness CA, Rudall PJ (2001). "The tapetum in basal angiosperms: early diversity". International Journal of Plant Sciences. 162 (2): 375–392. doi:10.1086/319580. S2CID84338737.
Christensen JE, Horner Jr HT, Lersten NR (1972). "Pollen wall and tapetal orbicular wall development in Sorghum bicolor (Gramineae)". American Journal of Botany. 59 (1): 43–58. doi:10.2307/2441229. JSTOR2441229.
Verstraete B, Moon HK, Smets E, Huysmans S (2014). "Orbicules in flowering plants: a phylogenetic perspective on their form and function". The Botanical Review. 80 (2): 107–134. doi:10.1007/s12229-014-9135-1. S2CID255562584.
Furness CA, Rudall PJ (2001). "The tapetum in basal angiosperms: early diversity". International Journal of Plant Sciences. 162 (2): 375–392. doi:10.1086/319580. S2CID84338737.