First of all, you should have read this link before you posted your questions
. Only one object per topic please. Putting several objects in the same input causes only confusion. viewtopic.php?f=1&t=10
Secondly, please polish your objects, they look awful.
Anyway, ГМ, Latin GM, is most likely Gerasim Mitrofanov, active in Moscow 1908-1917. MM is Mihail Maslov also active in Moscow 1899-1917