Phylogeny of chitinases and its implications for estimating horizontal gene transfer from chitinase-transgenic silver birch (Betula pendula)Katileena Lohtander, Hanna-Leena Pasonen, Markku K. Aalto, Tapio Palva, Ari Pappinen and Jouko RikkinenEnviron. Biosafety Res., 7 4 (2008) 227-239DOI: https://doi.org/10.1051/ebr:2008019