Erik von Scherling (1907–56) and Rotulus

Rotulus, vol.IV, no.1871 [Source]

Erik Edzard Floris Folkard von Scherling was the younger son of the Swedish Consul at Rotterdam, where he was born on 20 May 1907. When he left school he went to work for the bookseller Jacob Ginsberg in Leiden, where he specialised in Oriental books, and learnt Latin and Arabic.

Alphonse Labitte (1853- )

I occasionally encounter catalogue descriptions which mention an anonymous bookplate, variously described by different cataloguers, but recognisable from its device/motto on the scroll below the shield "EXCELSIOR":

Baltimore, Johns Hopkins University, John Work Garrett Library, Gar 6
http://www.digital-scriptorium.org