Arabi, Z., Ghahremaninejad, F., Rabeler, R.K. & Heubl, G. 2017. Seed micromorphology and its systematic significance in tribe Alsineae (Caryophyllaceae). Flora 234: 41-59.
Boissier, E. 1872. Flora Orientalis. Genava. Vol. 2. Genevae et Basileae: H. Georg. 1159 pp.
Browicz, K. 1993. Conspect and chorology of the genus Pyrus L. Arboretum Kornickie 38: 17-33.
Barthlott, W. 1981. Epidermal and seed surface characters of plants: systematic applicability and some evolutionary aspects. Nordic Journal of Botany 1: 345-355.
Cuizhi, C. & Spongberg, S. 2003. Pyrus in Flora of China. http://flora.huh.harvard.edu/china/PDF/PDF09/Pyrus.PDF
Elshihy, O., Sharaf, A. & Muzher, B. 2004. Morphological, anatomical and biochemical characterization of Syrian pear (Pyrus syriaca Boiss.) genotypes. Arabian journal of Biotechnology 7: 209-218.
Fang, X. & Yi-Xuan, Y. 1990. Observation on pollen morphology and exine ultrastructure of Pyrus in China. Chinese Journal of Botany 3: 33-41.
Fedorov, A. 1958. Pyrus L. in Takhtajan, A. (editor), Flora Armenii. Vol. 3. Erevan. pp. 235-254.
Grossheim, A. 1952. Flora Kavkaza. Vol. 5. Moskva- Leningrad. pp. 14-27.
Koehne, E. 1890. Die Gattunqen der Pomaceen. Berlin.
Iketani, H., Manabe, T., Matsuta, N., Akihama, T. & Hayashi, T. 1998. Incongruence between RFLPs of chloroplast DNA and morphological classification in east Asian pear (Pyrus spp.). Genetic Resources and Crop Evolution 45: 533-539.
Katayama, H., Tachibana, M., Iketani, H., Zhang, S. & Uematsu, C. 2012. Phylogenetic utility of structural alterations found in the chloroplast genome of pear: hypervariable regions in a highly conserved genome. Tree Genetics and Genomes 8: 313-326.
Khatamsaz, M. 1992. Pyrus L. in Assadi, M. Khatamsaz, M. & Maassoumi, A.A. (editors), Flora of Iran, No. 6. Research Institute of Forests and Rangelands, Tehran. pp. 181-200. (in Persian)
Kimura, T., Iketani, H., Kotobuki, K., Matsuta, N., Ban, Y., Hayashi, T. & Yamamoto, T. 2003. Genetic characterization of pear varieties revealed by chloroplast DNA sequences. The Journal of Horticultural Science and Biotechnology 78: 241-247.
Koul, K., Nagpal, R. & Raina, S. 2000. Seed coat microsculpturing in Brassica and allied genera (subtribes Brassicinae, Raphaninae, Moricandiinae). Annals of Botany 86: 385-397. doi:10.1006/anbo.2000.1197.
Maleev, P. 1971. Pyrus L. in Komarov, V. (ed.), Flora of U.S.S.R. Vol. 9. Academy of Science of the U.S.S.R. pp. 259-274.
Matsuta, N., Omura, M. & Akihama, T. 1982. Difference in micromorphological pattern on pollen surface of Japanese pear cultivars. Japanese Journal of Breeding 32: 123-128.
Murley, M. 1951. Seeds of the Cruciferae of North Eastern America. American Midland Naturalist 46: 1-81.
Popova, M., Kovacheva, D. & Anastassov, H. 1995. Anatomical studies of leaves of Pyrus L. species in Bulgaria. Proceedings of a jubilee symposium marking 100 years from the birthday of the academician Boris Stephanov (1894-1979): 109-113.
Rubtsov, G. A. 1944. Geographical distribution of the genus Pyrus and trends and factors in its Evolution. The American Naturalist 78: 358-366.
Schönbeck-Temesy, E. 1969. Pyrus L. in Rechinger, K.H. (editor.), Flora Iranica. No. 66. Akademische Druck
und Verlagsanstalt, Graz-Austria. pp. 27-36.
Tantawy, M. & Naseri, M. 2003. A contribution to the achene knowledge of Rosoideae (Rosaceae) LM and SEM. International Journal of Agriculture and Biology 5: 105-112.
Westwood, M.N. & Challice, J.S. 1978. Morphology and surface topography of pollen and anthers of Pyrus species. Journal of the American Society for Horticultural Science 103: 28-37.
Zamani, A., Attar, F., Ghahreman, A. & Maroofi, H. 2008. Anatomical studies of the genus Pyrus L. (Rosaceae) in Iran and its taxonomical implications. Iranian Journal of Botany 14: 132-142.
Zamani, A., Attar, F. & Maroofi, H. 2010. Pollen morphology of the genus Pyrus (Rosaceae) in Iran. Acta Biologica Szegediensis 54: 51-56.
Zamani, A., Attar, F. & Maroofi, H. 2012. A synopsis of the genus Pyrus (Rosaceae) in Iran. Nordic Journal of Botany 30: 310-332.
Zamani, A. 2016. Biosystemtic study on the genus Pyrus L. (Rosaceae) in Iran. Ph.D. thesis. University of Tehran. 243 pp.
Zamani, A., Attar, F. & Civeyrel, L. 2017. Leaf epidermis characters of Iranian Pyrus L. (Rosaceae) and their taxonomic implications. Genetic Resources and Crop Evolution 64: 159-176.
Zheng, X., Cai, D., Yao, L. & Teng, Y. 2008. Non-concerted ITS evolution, early origin and phylogenetic utility of ITS pseudogenes in Pyrus. Molecular Phylogenetics and Evolution 48: 892-903.
Zheng, X., Hu, C., Spooner, D., Liu, J., Cao, J. & Teng, Y. 2011. Molecular evolution of Adh and LEAFY and the phylogenetic utility of their introns in Pyrus (Rosaceae). BMC Evolutionary Biology 11: 255.
Zheng, X., Cai, D., Potter, D., Postman, J., Liu, J. & Teng, Y. 2014. Phylogeny and evolutionary histories of Pyrus L. revealed by phylogenetic trees and networks based on data from multiple DNA sequences. Molecular Phylogenetics and Evolution 80: 54-65.
doi: 10.1016/j.ympev.2014.07.009.