The combat is described in Efremovīs profile on the following site
http://airaces.narod.ru/winter/yefrem.htm
However, it says that 3 German fighters and 2 bombers were destroyed and two fighters were damaged. Two of the fighters were claimed by Efremov and the third was claimed by Laveykin. Seems that Laveykin also claimed one bomber.
Hope this helps
Jan