An elementary, geometric proof of the non-existence of a projective plane of order 6...1-9 Corrigendum to ``"On the enumeration of a class of toroidal graphs" [Contrib. Discrete Math. 13 (2018), no. 1, 79-119]...10-11 Partitioning the $5\times 5$ array into restrictions of circles...12-21 Construction of strongly regular graphs having an automorphism group of composite order...22-41 The polar of convex lattice sets...42-51 Pell Coding and Pell Decoding Methods with Some Applications...52--66 Total colouring of some cartesian and direct product graphs...67-71 On parity and recurrences for certain partition functions...72-79 Factorizations of complete graphs into cycles and 1-factors...80-89 On the first two entries of the f-vectors of 6-polytopes...90-101 Latin Squares and their Bruhat Order...102-120 3-uniform hypergraphs: modular decomposition and realization by tournaments...121-153 Nordhaus-Gaddum type inequalities for multiple domination and packing parameters in graphs...154-162 Closed formulas and identities on the Bell polynomials and falling factorials...163-174 Some combinatorial properties of hexagonal lattices...175-182