On dipositronium and molecular hydrogen: similarities and differences António J.C. Varandas, João da Providência, Marta Brajczewska and João P. da Providência Eur. Phys. J. D, 69 4 (2015) 114 Published online: 21 April 2015 DOI: 10.1140/epjd/e2015-50818-0