No.1777
What should I read to get a good understanding of Stalin's thought (specifically socialism in one country)
No.1781
The most obvious is the 600-page "Problems of Leninism" compilation the USSR itself put out, containing many of his important writings:
https://docs.google.com/file/d/0B1ZP6ZurgOg-TlQtNUpqeXRRZHM/editOn the issue of socialism in one country specifically, here's one article:
http://www.unz.org/Pub/Communist-1939jun-00542