Hi,
You may want to start with this basic introduction about bird ringing/banding:
Cleminson, A., & Nebel, S. (2012).
Bird Banding.
Nature Education Knowledge 3(8): 1.
The article about the father of bird ringing that you are looking for was published in the proceedings of the International Conference on the Results and Perspectives of Bird Ringing” named “Bird Ringing 100 Years” that was held in Helgoland, Germany in autumn 1999. The proceedings of the conference were published in a special issue in the
Ardea journal in 2001 (all articles are free, but you are requested to register by an email to download them). Here are some selected papers:
Preuss N.O. (2001).
Hans Christian Cornelius Mortensen: Aspects of his life and of the history of bird ringing.
Ardea 89 (special issue): 1-6.
Bairlein F. (2001).
Results of bird ringing in the study of migration routes.
Ardea 89 (special issue): 7-19.
Baillie S.R. (2001).
The contribution of ringing to the conservation and management of bird populations: A review.
Ardea 89 (special issue): 167-184.
If you search the titles of these articles in Google Scholar, you will find many more interesting papers that discuss bird ringing.
To celebrate 100 years of bird ringing in Britain and Ireland, BTO dedicated a special issue of its journal
Ringing & Migration to this event (all articles are free to download). There are about a dozen of articles including:
Bairlein, F. & Schaub, M. (2009).
Ringing and the study of mechanisms of migration.
Ringing & Migration 24 (3): 162-168.
You can also see this paper from the 23rd IOC Proceedings:
Fiedler W. & Pulido F. 2006.
S19-3 Bird ringing as a means for studying the evolution of avian migration — potentials, limits and prospects.
Acta Zoologica Sinica 52 (Supp.): 345–349.
This review paper also discusses ringing among other things:
Greenwood J.J.D. 2007.
Citizens, science and bird conservation.
Journal of Ornithology 148: S77–S124.
This review article also discusses ringing in relation to bird migration:
Busse P. 2001.
European passerine migration system – what is known and what is lacking.
Ring 1-2: 3–36.
Good luck,