I am currently writing a paper, for which my title and core problem is spelled differently in American and British English.
I don't worry about my professor preferring one way of writing over the other, as I'm not residing in an English-speaking country, but:
After all, my paper is being written in English, even it won't be published. Thus I wonder:
Is there a "standard procedure" for such cases, at least in US Ivy League universities or in certain citation styles? (I am currently using APA, 6th (our prof. didn't prescribe any specific citation style) as it suits my personal preference of how a reference should be cited and displayed.)
I will definitely mention both words in the "keywords" area, but other than that I will go with one spelling, namely the American English one. The word is "harmonization", if that should be important.
Sorry for my lack of initial research, I found this SE question though.