what is official lds mormon church doctrine?

i call it the "official doctrine" dilemma:

where does it say what official lds doctrine is?

"source X"

where does it say that "source X" is official doctrine?

"source Y"

where does it say that "source Y" is official doctrine?

"source Z"

ad infinitum or "it doesnt".

most people, when asked this question cite this source:
http://fairlds.org/FAIR_Brochures/What_is_Mormon_Doctrine.pdf

the problem is that michael ash isnt an official spokesman for the lds church so this article about what is official doctrine isnt official.

if someone suggests this link:
http://newsroom.lds.org/article/approaching-mormon-doctrine

then my reply is:
is everything on newsroom.lds.org official doctrine? if so, where does it say that? who says this "authorless" article is official doctrine? is everything on lds.org official doctrine? if so, where does it say that?

is everything in the scriptures even official doctrine? what about polygamy? what about stoning your child if he doesnt obey you? see the dilemma?

IMPORTANT: when debating with an apologist, dont let the apologist set the rules of what is official doctrine or not. dont play by their rules. state something like: just so you know, i intend to take apostles and prophets of god at their word that what they say is official revelation from god when speaking in public or publicly publishing their teachings (independent of when the teachings were given--dead prophets and apostles count just as much as living), in addition to all "scriptures" in their original, "most perfect"/"directly revealed by god" versions--all changes to these sources will be disregarded. if the changes were purely spelling errors or dont change the meaning of the context then it wont matter anyways.