diff --git a/solidity/token_standards/README.md b/solidity/token_standards/README.md
index 6fdf033..c79680b 100644
--- a/solidity/token_standards/README.md
+++ b/solidity/token_standards/README.md
@@ -1,31 +1,41 @@
-## Token standards
+## ethereum token standards
 
-<br>
+### tl; dr
 
-* ERC stands for Ethereum request for comments. 
-* These are technical documents written by Ethereum developers for Ethereum community. 
+* EIP stands for Ethereum Improvement Proposals.
+* ERC stands for Ethereum request for comments (technical documents written by Ethereum developers for Ethereum community).
 * Each such document contains a set of rules required to implement tokens for the Ethereum ecosystem.
-* You can say ERC is a specific type of EIP.
+
 
 
 <br>
 
 ---
 
-### [ERC20](https://github.com/bt3gl-labs/Blockchain-Hacking-Toolkit/blob/main/Solidity-Expert/Token-standards/erc20.md)
+### erc-20
 
-* In the case of ERC20, a transaction sending ether to an address changes the state of an address. A transaction transferring a token to an address only changes the state of the token contract, not the state of the recipient address.
 
+* In the case of ERC20, a transaction sending ether to an address changes the state of an address.
+    - a transaction transferring a token to an address only changes the state of the token contract, not the state of the recipient address.
+* one of the main reasons for the success of EIP-20 tokens is in the interplay between `approve` and `transferFrom`, which allows for tokens to not 
+only be transferred between externally owned accounts (EOA).
+   - but to be used in other contracts under application specific conditions by abstracting away `msg.sender` as the mechanism for token access control.
+*  a limiting factor lies from the fact that the EIP-20 `approve` function is defined in terms of `msg.sender`. 
+    - this means that user’s initial action involving EIP-20 tokens must be performed by an EOA. 
+    - if the user needs to interact with a smart contract, then they need to make 2 transactions (`approve` and the smart contract internal call `transferFrom`), with gas costs.
 
 <br>
 
 ---
 
-### [ERC777](https://github.com/bt3gl-labs/Blockchain-Hacking-Toolkit/blob/main/Solidity-Expert/Token-standards/erc777.md)
+### in this dir
 
+* [ERC20](erc20.md)
+* [ERC777](erc777.md)
+* [ERC721](erc721.md)
 
 <br>
 
 ---
 
-### [ERC721](https://github.com/bt3gl-labs/Blockchain-Hacking-Toolkit/blob/main/Solidity-Expert/Token-standards/erc721.md)
+### resources