Subgroup theorems and graphs -- Counting unlabeled acyclic digraphs -- Golay sequences -- The knotted hexagon -- On skew room squares -- Some new constructions for orthogonal designs using circulants -- A note on asymptotic existence results for orthogonal designs -- The spectrum of a graph -- Latin squares composed of four disjoint subsquares -- The semi-stability of lexicographic products -- On rings of circuits in planar graphs -- Sum-free sets in loops -- Groups with stable graphs -- A problem in the design of electrical circuits, a generalized subadditive inequality and the recurrence relation j(n,m)=j([n/2],m)+j([n+1/2],m)+j(n,m-1) -- Orthogonal designs in order 24 -- A schrรถder triangle: Three combinatorial problems -- A combinatorial approach to map theory -- On quasi-multiple designs -- A generalisation of the binomial coefficients