Regularized adelic formulas for gamma and beta functions for arbitrary
quasicharacters (either ramified or not) and in an arbitrary field of algebraic
numbers are concretized as applied to one-class quadratic fields (and to the
field of rational numbers). Applications to 4-tachyon tree string amplitudes,
to the Veneziano (open strings) and Virasoro (closed strings) amplitudes as
well as to massless 4-particle amplitudes of the Ramond-Neveu-Schwarz
superstring and a heterotic string are discussed. Certain relations between
different superstring amplitudes are established.