THE STRUCTURE OF A CONTROLLABILITY REGION Статья ZVERKIN A.M., ROZOVA V.N. Differential Equations. Том 18. 1982. С. 186-190
DETERMINATION OF THE FORCE FUNCTION FROM A GIVEN INTEGRAL OF THE EQUATION OF MOTION Статья GALIULLIN A.S. Differential Equations. Том 18. 1982. С. 530-532