Comparative study of pollination biology of two closely related alpine Primula species, Primula beesiana and P. bulleyana (Primulaceae)
Zhi-Kun WU,Chang-Qin ZHANG
J Syst Evol . 2010, (2): 109 -117 .  DOI: 10.1111/j.1759-6831.2010.00069.x