This is referred to as secondary referencing. As with most secondary referencing this is to be discouraged as far as possible. You should always aim to refer to the original publications if you can as this is considered to be better academic practice. There are instances where secondary referencing has to be provided in the absence of referring to original publications. This could be due to the age of the publication (see Clay example below), language, licensing restrictions and availability (see Katsarou example below).
Advice from OSCOLA FAQs:
If it is not possible to find the original source, cite the source as cited in the secondary source then in brackets put ‘as cited in’ then cite the secondary source including the page number. For example:
Quoted in WL Clay, The Prison Chaplain: A Memoir of the Reverend John Clay (London 1861) 554 (as cited in M Wiener, Reconstructing the Criminal Culture, Law and Policy in England 1830–1914 (CUP 1990) 79).
or (my example):
Katsarou v Greek State (1998) Case No 34581 as cited in Takis Tridimas, ‘Knocking on Heaven’s Door: Fragmentation, Efficiency and Defiance in the Preliminary Reference Procedure ’ (2003) 40 CMLR 9, 43.
