Asymptotic behavior of CLS estimators for $2$-type doubly symmetric critical Galton-Watson processes with immigration

Bernoulli 2014, Vol. 20, No. 4, 2247-2277 In this paper, the asymptotic behavior of the conditional least squares (CLS) estimators of the offspring means $(\alpha,\beta)$ and of the criticality parameter $\varrho:=\alpha+\beta$ for a $2$-type critical doubly symmetric positively regular Galton-Watson branching process with immigration is described.