Preface (S. Ejaz Ahmed, Francisco Carvalho, Simo Puntanen) -- Further properties of the linear sufficiency in the partitioned linear model (Augustyn Markiewicz, Simo Puntanen) -- Hybrid model for recurrent event data (Ivo Sousa-Ferreira, Ana Maria Abreu) -- A new look at combining information from stratum submodels (Radosław Kala) -- Ingram Olkin (1924–2016): An appreciation for a people person (Simo Puntanen, George P. H. Styan) -- A notion of positive definiteness for arithmetical functions (Mika Mattila, Pentti Haukkanen) -- Some issues in generalized linear modeling (Alan Agresti) -- Orthogonal block structure and uniformly best linear unbiased estimators (Sandra S. Ferreira, Dário Ferreira, Célia Nunes, Francisco Carvalho, João Tiago Mexia) -- Hadamard matrices on error detection and correction: Useful links to BIBD (Carla Francisco, Teresa A. Oliveira, Amílcar Oliveira, Francisco Carvalho) -- Covariance matrix regularization for banded Toeplitz-structure via Frobenius-norm discrepancy (Xiangzhao Cui, Zhenyang Li, Jine Zhao, Defei Zhang, Jianxin Pan) -- Penalized relative error estimation of a partially functional linear multiplicative model (Tao Zhang, Yuan Huang, Qingzhao Zhang, Shuangge Ma, S. Ejaz Ahmed) -- High-dimensional regression under correlated design: An extensive simulation study (S. Ejaz Ahmed, Hwanwoo Kim, Gökhan Yıldırım and Bahadır Yüzbaşı) -- An efficient estimation strategy in autoregressive conditional Poisson model with applications to hospital emergency department data (S. Ejaz Ahmed, Khalifa Es-Sebaiy, Abdulkadir Hussein, Idir Ouassou, Anne Snowdon). .