Tibor Sekelj ( in Hungarian : SzÃ kely Tibor ) ( 14 February 1912 â `` 23 September 1988 ) was an explorer , writer and lawyer . Tibor Sekelj ( in Hungarian : SzÃ kely Tibor ) ( 14 February 1912 â `` 23 September 1988 ) was an explorer , esperantist , writer and lawyer of Jewish descent .