J. D. Hayler, S. L. B. Howie, R. G. Giles, A. Negus, P. W. Oxley, T. C. Walsgrove, M. Whiter: Development of Large-Scale Syntheses of Ropinirole in the Pursuit of a Manufacturing Process. In: Org. Process Res. Dev.Band2, Nr.1, 1998, S.3–9, doi:10.1021/op970037c.