Vladimir Jurko Glaser (1924-1984), theoretical physicist in the field of quantum fields theory, published one of the first monographs on Quantum Electrodynamics in the world (Kovarijantna kvantna elektrodinamika, Zagreb 1955, written in Croatian), at the age of 31. On p. 8 of the book he mentioned that the existence of positronium has been theoretically predicted by Stjepan Mohorovicic in 1934.

He was head of the Department of Theoretical Physics at the Rudjer Boskovic Institute in Zagreb. In 1957 he found permanent employment at the Department of Theoretical Physics in CERN in Geneva. Letters sent to Glaser by Wolfgang Pauli (nicknamed “the sword of theoretical physics”) show Glaser’s outstanding scientific status among theoretical physicists of his time. On the occasion of Glaser’s death, during the commemoration held in CERN, prof. Henry Epstein said that he does not understand Croatian, but when in need for details and formulae, he prefers to consult Glaser’s book (written in Croatian!), since it is reliable in all details. For more information see here (in Croatian).