Some old papers are almost impossible to find, since publishers are not active anymore and no one published the papers in online depositories.
Here, I will collect some old hard-to-find papers about salmonid biology, which I believe no one would object to having accessible online (if so, please contact me and I will delete them).
Stuart, T.A. 1953. Spawning migration, reproduction and young stages of loch trout (Salmo trutta L.). Freshwater and Salmon Fisheries Research 5:1-39
Nilsson, N.-A. 1956 On the feeding habits of trout in a stream of Northern Sweden. Report - Insititute of Freshwater Research, Drottningholm 37:154-166
Kalleberg, H. 1958. Observations in a stream tank of territoriality and competition in juvenile salmon and trout (Salmo salar L. and S. trutta L.). Report - Insititute of Freshwater Research, Drottningholm 39:55-98
Alm, G. 1959. Connection between maturity, size, and age in fishes - experiments carried out at the Kälarne Fishery Research Station. Report - Insititute of Freshwater Research, Drottningholm 40:5-145
Lindroth, A. & Bergström, E. 1959. Notes on the feeding technique of the Goosander in streams. Report - Insititute of Freshwater Research, Drottningholm 40:165-175
Gibson, R.J. & Haedrich, R.L. 1988. The exceptional growth of juvenile Atlantic salmon (Salmo salar) in the city waters of St. John's, Newfoundland, Canada. Polskie Archiwum Hydrobiologii 35:385-407