Il. Buchbinder et al., BRST-BFV ANALYSIS OF ANOMALIES IN BOSONIC STRING THEORY INTERACTING WITH BACKGROUND GRAVITATIONAL-FIELD, Physics letters. Section B, 353(4), 1995, pp. 457-462
A general BRST-BFV analysis of the anomaly in string theory coupled to
background fields is carried out. An exact equation for the c-valued
symbol of the anomaly operator is found and the structure of its solut
ions is studied.