Bahçecitapar, M., Karadag, Özge . and Aktas, S. 2015. Specification of Variance-Covariance Structure in Bivariate Mixed Model for Unequally Time-Spaced Longitudinal Data. International Journal of Statistics in Medical Research. 4, 4 (Nov. 2015), 370–377. DOI:https://doi.org/10.6000/1929-6029.2015.04.04.6.