The mixed model of analysis of variance is a linear model in which some terms that would otherwise be unknown constants are, in fact, unobservable realizations of random variables. Estimation procedures for the constants and for the realized random variables are reviewed, with emphasis on their matrix features. © 1997 Elsevier Science Inc.
Searle, S. R. (1997). The matrix handling of BLUE and BLUP in the mixed linear Model. Linear Algebra and Its Applications, 264(1–3), 291–311. https://doi.org/10.1016/S0024-3795(96)00400-4