Hi
Our National Archives website has an enlistment record of interest.
It is for a man names GEORGE CONSTANTINE PIERCE, letter carrier born in Sydney about 1898.
His father GRAHAM HUNTER PIERCE is his next of kin and he lives at TURRAMURRA.
Because he is underage his parents signatures are required and his mother signs as BERTHA G (GEORGINA) PIERCE.
Later in the file, in 1917, GEORGE confesses to using an assumed name and his real surname is MASTERS.
Asworn declaration by his father GRAHAM HUNTER PIERCE refers to his son and is dated 31/7/1917.
This is the death you refer to above.
In 1911 PIERCE, GRAHAM H. father JOHN mother MARGARET SYDNEYref. 4272
Their marriage
In 1908. GRAHAM H . PIERCE to BERTHA G. MASTERS ref. 3550
Death of BERTHA
1950 PIERCE, BERTHA GEORGINA (STRINGFELLOW)aged 71 YRS WAHROONGAat CHATSWOOD ref. 18394
Sue