Stephen P. Coburn, J. Dennis Mahuren and Tomas R. Guilarte. "Vitamin B-6 content of plasma of domestic animals determined by HPLC, enzymatic and radiometric microbiological methods." Journal of Nutrition Vol. 114 Iss. 12 (1984) p. 2269 - 2273
Available at: http://works.bepress.com/toms-guilarte/143/