一篇額外的參考文獻:Beerling, D.J., Osborne, C.P. and Chaloner, W.G. (2001) Evolution of leaf-form in land plants linked to atmospheric CO2 decline in the Late Palaeozoic era. Nature, 410 (6826). pp. 287-394. [全文]
另請參考Beerling & Fleming (2006)根據分子與細胞學正據對於這個演化假說的評述
