Robinson J. M. Lignin, land plants, and fungi: biological evolution affecting Phanerozoic oxygen balance // Geology, 1990, V. 18, №7, 607–610.
49
Beerling D. J. et al. Carbon isotope evidence implying high O2/CO2 ratios in the Permo-Carboniferous atmosphere // Geochimica et Cosmochimica Acta, 2002, V. 66, №21, 3757–3767.