See for example,

Gamow, G. 1946, Phys. Rev. 70, 571.

Alpher, R.A. and Herman, R.C. 1950, Rev. Mod. Phys. 22, 153.

Hayashi, C. 1950, Prog. Theor. Phys. 5, 224.

Alpher, R.A., Follin, J.W. and Herman, R.C. 1953, Phys. Rev. 92, 1347.

for the details of the development of BBN from an attempt to explain observed abundances.