Ludwig, K.R. and Titterington, D.M., 1994.
Calculation of 230Th/U isochrons, ages, and errors.
Geochimica et Cosmochimica Acta,
58(22), pp.5031-5042.
York, D., Evensen, N.M., Martinez, M.L. and De Basabe Delgado, J., 2004.
Unified equations for the slope, intercept, and standard errors of the
best straight line.
American Journal of Physics, 72(3), pp.367-375.