Källén writes on certain mathematical problems of the Lee model.
Källén, GunnarKällén attempts to clarify for himself the contents of the papers by Landau and his collaborators.
Källén, GunnarKällén talks about Thirring's work on quantum electrodynamics.
Källén, GunnarKällén enumerates various points of Heisenberg's theory, with which he does not agree.
Källén, GunnarKällén talks about calculation on an integral-representation of the S$_{c}$-function, avoiding the complex method of integration.
Källén, GunnarKällén encloses a manuscript dealing with the contents of his last letter of the 12 December 1949, in addition to a calculation on bosons in an external field.
Källén, GunnarKällén talks about some general observations on the mathematical formalism of the Lee model.
Källén, GunnarKällén writes about his work on quantum electrodynamics and especially about renormalization.
Källén, GunnarKällén writes on an interim report on his work on quantum electrodynamics.
Källén, GunnarKällén criticizes Thirring's remarks about his theory communicated by Pauli.
Källén, Gunnar