found: His Relatório da Comissão Exploradora do Planalto Central do Brasil, 1984:t.p. (Luiz Cruls)
found: Grande Larousse Cultural, 1998:v.7, p.1712 (Cruls (Louis Ferdinand, geógrafo e astrônomo belga radicado no Brasil b. Diest 1848 - d. Paris 1908; engenheiro do Exército Belga até 1874)
found: Brazil. Comissão Exploradora do Planalto Central do Brasil. Relatório, 1947:t.p. (L. Cruls)
found: Dic. bib. port., 1893:v. 16, p. 13 (b. in Diest (Brabant, Belgium), 01/21/1843; became a Brazilian citizen in 1881; military engineering; director of the imperial observatory)
found: Wikipedia, viewed August 5, 2015(Belgian-born Brazilian astronomer; born January 21, 1848 in Diest, Belgium; died June 21, 1908)
