Actually, there's no one commonly agrred on correct way to spell this composer's name, simply because there's no commonly agreed on way to transliterate Russian names from the Cyrillic alphabet to English.
This is true of of other famous Russian composers.
I've studied Russian, am pretty familiar with the language even if I don't speak ir fluently , and can read Cyrillic.
Sometimes it's spelled Rachmaninoff and sometimes Rachmaninov,
and the ch , which represent the same sound asin Chutzpah is sometimes written as kh , and this spelling is sometimes used.
Mussorgsky should actually be spelled with only one s , and Prokofiev is sometimes spelled Prokofieff .
Tchaikovsky is sometimes written as Chaykovsky .
Very confusing .
