by Pijls, B. G., Kok, F. P., Penning, L. I. F., Guldemond, N. A., Arens, H. J.
Published in Journal of clinical ultrasound (01.03.2010)

by van Heesewijk, H P, Smit, F W, Heitbrink, M A, Kok, F P
Published in American journal of roentgenology (1976) (01.01.1990)

by P. D. F. Kok
Published in Bothalia (10.11.1981)

by G. Germishuizen, P. J. Robbertse, P. D. F. Kok
Published in Bothalia (19.12.1989)

by van Heesewijk, H P, Smit, F W, Heitbrink, M A, Kok, F P
Published in AJR. American journal of roentgenology (01.01.1990)

by G. Germishuizen, P. D. F. Kok, P. J. Robbertse
Published in Bothalia (01.12.1989)

by Botha, R., Kok, P. D. F., Ellis, R. P.
Published in Suid-Afrikaanse tydskrif vir natuurwetenskap en tegnologie (18.03.1986)

by Van Wyk, A.E, Robbertse, P.J, Kok, P.D.F
Published in Botanical journal of the Linnean Society (1982)