A Knowledge graph representation of baseline characteristics for the Dutch proton therapy research registry. - Matthijs Sloep; Petros Kalendralis; Ananya Choudhury; Lerau Seyben; Jasper Snel; Nibin Moni George; Martijn Veening; Johannes A. Langendijk; Andre Dekker; Johan van Soest; Rianne Fijten (CoRR, 2021)