" Christelijke Belgische Diamantbewerkerscentrale, 1956, in-8°, 24 x 15.5 cm, frontispiece, 272 pp, 152 ills., 20 pl. h/t, red boards, gilt lettering. A thorough study of cleaving, sawing, cutting and polishing diamond. The authors were ""Laureaten van de Arbeid"" and taught at technical schools. Text in Dutch, manual on diamond-working."