||Misra JB. Integrated operation of the photorespiratory cycle and cytosolic metabolism in the modulation of primary nitrogen assimilation and export of organic N-transport compounds from leaves: a hypothesis. J Plant Physiol. 2014 Feb 15 171(3-4):319-28. doi: 10.1016/j.jplph.2013.09.008. p.322 right column 2nd paragraphPubMed ID24157314
||T.D. Sharkey Estimating the rate of photorespiration in leaves Physiol Plant, 73 (1988), pp. 147–152
||p.322 right column 2nd paragraph:"According to Sharkey (primary source), it is reasonably accurate to assume that the CO2 concentration at the site of carboxylation is 0.6 times that of the ambient CO2 concentration. Therefore, at the current ambient levels of CO2 (385 ppm v/v), the concentration at the carboxylation site should be 231 ppm (=10.3 μM)."