He, Y., Helfrich, W. & Bremer, E., 2019, Cancer Immunosurveillance: Methods and Protocols.Humana Press, blz. 335-34713 blz. (Methods in Molecular Biology).
Helfrich, W., Molema, G. & de Leij, L., 1998, Alternative approaches to human blood resources in clinical practice. Smit Sibinga, C. T., Fratantoni, J. D. & Das, P. C. (uitgave). Dordrecht/Boston/London: Kluwer Academic Publishers, blz. 103 - 11816 blz.