allocation to create B<BIGNUM>s is rather expensive when used in
conjunction with repeated subroutine calls, the B<BN_CTX> structure is
used. This structure contains B<BN_CTX_NUM> B<BIGNUM>s, see
-L<BN_CTX_start(3)|BN_CTX_start(3)>.
+L<BN_CTX_start(3)>.
=head2 Low-level arithmetic operations
=head1 SEE ALSO
-L<bn(3)|bn(3)>
+L<bn(3)>
=cut