||p.149 right column 3rd paragraph:"When the CO2 level is 210 ppm, φ is 0.41. If [investigators] use a specific example of a leaf photosynthesizing at 30µmol/m^2/s, with a rate of non-photorespiratory respiration of 1µmol/m^2/s, [they] can use eq. 8 to calculate the rate of oxygenation to be 16µmol/m^2/s. Since one CO2 is released for every two oxygenations, the rate of photorespiration is 8µmol/m^2/s. Thus the rate of photorespiratory CO2 release is 26% of the rate of net CO2 assimilation."