The fact that Theodorus de Kruijf is the same person as Dirk de Kruijf is deducted from (a.o.) the birth, marriage and death record of daughter Elisabeth, born 14 Mar 1867 as daughter of Dirk, married Jan van Eck being daughter of Dirk, and died 11 Mar 1938, being the widow of Jan van Eck and daughter of Theodorus. Different sources gave different parents with equal birthdates for other children too.