Tooley’s dictionary of mapmakers, 2004 v. 4, p. 8 (Ram [De Ram], Johannes de (1648-1693). Engraver, publisher, globe maker, and art dealer of Amsterdam)
OCLC, Aug. 20, 2007 : (hdg.: Ram, J. de,18 juni 1648-15 mei 1693; Ram, Johann de; Ram, Johannes de; usage: Johanne de Ram)