found: Een kabinet van Rijnstreek gezichten, 1969:title page (samengesteld door Th. Laurentius)
found: Renburanto dōbanga ten, 1993:page 10 (Theo Laurentius; Teo Raurentsiasu [in kana]; researcher of paper and water marks) page 174 (caption under photo: researcher Th. Laurentius)
found: Italian watermarks 1750-1860, 2016:title page (Theo Laurentius) jacket flap (Theo Laurentius; active as a paper researcher for over 50 years; has published several studies on watermarks and paper)
found: Watermarks, 1600-1650, found in the Zeeland Archives, 2007:title page (Theo and Frans Laurentius)
found: Kunsthandel Th. Laurentius website, viewed October 31, 2016:link to Over Ons page (kunsthandelaar Theo Laurentius (1936); Middelburg, Netherlands)