Efim Dmitriyevich Bogolyubov ( Russian : Ефим Дмитриевич Боголюбов ; also Romanized Bogoljubov , Bogoljubow ; April 14 , 1889 - June 18 , 1952 ) was a Russian chess grandmaster who won numerous events and played two matches against Alexander Alekhine for the world championship .
Efim Bogolyubov ( 14 April 1889 - 18 June 1952 ) was a Ukrainian-German chess grandmaster who won numerous events and played two matches with Alexander Alekhine for the world championship .