Files Not present on the mentioned Directory

[delixus-valliammal1]

There is lot of files are not present.

We need this files of solidity, so that this book can be used nicely
import './SampleToken.sol';
import 'openzeppelin-solidity/contracts/crowdsale/emission/MintedCrowdsale.sol';
import 'openzeppelin-solidity/contracts/crowdsale/
distribution/PostDeliveryCrowdsale.sol';

Where is MintedCrowdSale.sol, and PostDeliveryCrowdsale.sol?

Can you please clarify?

thanks