Highly efficient pollination by bumblebees ensures seed production in Pedicularis lachnoglossa (Orobanchaceae), an early-flowering Himalayan plant
Wen-Bin YU, De-Zhu LI, Hong WANG
J Syst Evol . 2012, (3): 218 -226 .  DOI: 10.1111/j.1759-6831.2012.00180.x