Yukawa's heavy quantum and the mesotron, 1935-1937 / by Helmut Rechenberg and Laurie M. Brown.
Abstract:
'In this paper we describe this central episode in the history of elementary particle physics from Yukawa's proposal, published in 1935, to the year 1937 when particles resembling the quanta of the U-field were detected in the cosmic rays.'
Centaurus Vol. 33 (1990), p. 214-252