The Volga: Southeast of the trailer there is a gas station that is also a bandit hideout. Enter the station through the left window. The note will be right in front of you on the overturned locker. You can also follow the rail from Duke's train car until you reach the next overpass, and then simply walk east until you reach the gas station.
Nikolay, this can't go on like this forever, you must understand! We must either remove that sign or set up a roadblock or do something - the people keep on coming in! The last family to arrive had to push their car for six kilometers, and they almost got violent when they found out that we have no gas.
Yes, we were a government-designated civilian emergency supply point, and it's not our fault that the tanker never arrived, but you can't expect me to explain that to all the people who come in driving on fumes only to find out that they'll have to abandon their last possessions!
Luckily, we still have some of the emergency rations left in that train stuck on the bridge. Incidentally, that's exactly where I am going to move with some of the more agreeable people here - so when you finally catch that tanker you can look me up there.
Or, better yet, just bring it over there - we're going to need that gas if we want to live through the winter.