CatCatHead wrote:

Andyluo wrote:

vincentwant wrote:

yes it is allowed (tstst 2018/8 i think requires it)

I was curious about citing sources in general.

can you just site anything thats from a book or smth?

Actually in the TST level you can cite anything if you remember the right place like in lemma 4.13 in the EGMO book written by evan chen balabala. But in the USAJMO/USAMO level you may be marked wrong as there are too much students, so I do not recommond to use not famous lemma in USAJMO and USAMO. (Zsigmondy is famous enough i think)

Note that citing aops handouts does not count, if its a published book yes an aops handout so stuff like muricaaaa I dont believe is qoutable.