cppreference

 

https://en.cppreference.com/w/

[1] https://en.cppreference.com/w/cpp/language/reference_initialization#Lifetime_of_a_temporary
[2] http://openx.huawei.com/communityWikiDetails?communityId=41&ibid=SPE1000000176&wikiId=1184&navid=NVI1000004470
[3] https://en.cppreference.com/w/cpp/memory/shared_ptr/get
[4] https://en.cppreference.com/w/cpp/language/copy_elision
[5] https://www.boost.org/doc/libs/1_76_0/libs/rational/
[6] https://www.boost.org/doc/libs/1_76_0/libs/utility/operators.htm