The IUPAC atom names for amino acids and
other essential information for the description
of polypeptide conformations can be found in:
IUPAC-IUB Commission on Biochemical Nomenclature. (1970).
Abbreviations and symbols for the description of the
conformation of polypeptide chains: Tentative rules (1969).
Note that this was published in September 1970.
The title unfortunately implies that these rules will be
or have been superseded.
I know of no more definitive publication nor do I find
any differences from presently accepted standards.