  We prove an explicit formula for a projection of singular vectors in the
Verma module over a rank 2 Kac-Moody Lie algebra onto the universal enveloping
algebra of the Heisenberg Lie algebra and of $sl_{2}$ (Theorem 3). The formula
is derived from a more general but less explicit formula due to Feigin, Fuchs
and Malikov [Funct. Anal. Appl. 20 (1986), no. 2, 103-113]. In the simpler case
of $A_{1}^{1}$ the formula was obtained in [Fuchs D., Funct. Anal. Appl. 23
(1989), no. 2, 154-156].
