  We give an explicit construction of exact cooperative regenerating codes at
the MBCR (minimum bandwidth cooperative regeneration) point. Before the paper,
the only known explicit MBCR code is given with parameters $n=d+r$ and $d=k$,
while our construction applies to all possible values of $n,k,d,r$. The code
has a brief expression in the polynomial form and the data reconstruction is
accomplished by bivariate polynomial interpolation. It is a scalar code and
operates over a finite field of size $q\geq n$. Besides, we establish several
subspace properties for linear exact MBCR codes. Based on these properties we
prove that linear exact MBCR codes cannot achieve repair-by-transfer.
