Readers should cite both the Bio-protocol preprint and the original research article where this protocol was used:

Weyershaeuser, J and Köhn, M(2021). Establishment of PD-1 Flag-tagged constructs. Bio-protocol Preprint. bio-protocol.org/prep1166.
Marasco, M., Berteotti, A., Weyershaeuser, J., Thorausch, N., Sikorska, J., Krausze, J., Brandt, H. J., Kirkpatrick, J., Rios, P., Schamel, W. W., Köhn, M. and Carlomagno, T.(2020). Molecular mechanism of SHP2 activation by PD-1 stimulation . Science Advances 6(5). DOI: 10.1126/sciadv.aay4458