numbered specification drawings (specifications 313 and 525), signed by J.Th.J. Cuypers and P.J.J.M. Cuypers, dating 1921-1924, 1930, scale 1 in 10, 1 in 20, 1 in 50, 1 in 100, 1 in 200, 1 in 500, 1 in 1000.