主题：【求助】（已应助）求助4篇英文文献，每篇5分

1. Takuo Ozaki, Shizuko Ambe, S. Enomoto, Y. Minai,  S. Yoshida, Y. Makide, Multitracer study on the uptake mechanism of yttrium and rare earth elements by autumn fern, Radiochimica Acta, 2002, 90 (5): 303-307.
http://www.atyponlink.com/OLD/doi/abs/10.1524/ract.2002.90.5_2002.303
2. Zhenggui Wei, Jonathan Woonchung Wong, Haiyan Zhao, Huijuan Zhang, Huixin Li and Feng Hu, Separation and Determination of Heavy Metals Associated with Low Molecular Weight Chelators in Xylem Saps of Indian Mustard ( Brassica juncea ) by Size Exclusion Chromatography and Atomic Absorption Spectrometry, Biological Trace Element Research, 2007, 118: 146-158.
https://commerce.metapress.com/content/385x444l9520677r/resource-secured/?target=fulltext.pdf&sid=rpng0d45fpafyf45b2mjf3rt&sh=www.springerlink.com
3. Tommy Olsson, Rare earth elements in forest-floor herbs as related to soil conditions and mineral nutrition, Biological Trace Element Research, 2005, 106: 177-191.
http://www.springerlink.com/content/u13w351855v85j12/
4. Zhenggui Wei, Fashui Hong, Ming Yin, Huixin Li, Feng Hu, Guiwen Zhao and Jonathan Woonchung Wong,  Structural differences between light and heavy rare earth elment binding chlorophylls in naturally grown fern Dicranopteris linearis, Biological Trace Element Research, 2005,106:279-297.
http://www.springerlink.com/content/p2681rl406g83785/