  Let X be an L_1-predual space and let K be a countable linearly independent
subset of the extreme points of its closed dual ball. It is shown that if the
norm-closed linear span Y of K is w^*-closed in X^*, then Y is the range of a
w^*-continuous contractive projection in X^*. This result is applied in order
to provide new and simpler proofs of the results of Lazar, Lindenstrauss and
Zippin on the embedding of C(K) spaces into X.
