feat: add cross-linking with to tblkch whitepaper

foundations/whitepapers/tblkch.mdx

@@ -20,7 +20,7 @@ This document provides a detailed description of the TON Blockchain, including i
 
 [Chapter 1](#1-overview) provides a general overview of the TON Blockchain and its design principles, with particular attention to the introduction of compatibility and validity conditions and the implementation of message delivery guarantees. More detailed information, such as the TL-B schemes that describe the serialization of all required data structures into trees or collections ("bags") of cells, is provided in subsequent chapters, culminating in a complete description of the TON Blockchain (shardchain and masterchain) block layout in [Chapter 5](#5-block-layout).
 
-A detailed description of the elliptic curve cryptography used for signing blocks and messages, also accessible through TVM primitives, is provided in [Appendix A](#a-elliptic-curve-cryptography). TVM itself is described in a separate document (cf. [[4](#ref-4)]).
+A detailed description of the elliptic curve cryptography used for signing blocks and messages, also accessible through TVM primitives, is provided in [Appendix A](#a-elliptic-curve-cryptography). TVM itself is described in a [separate document](/foundations/whitepapers/tvm).
 
 Some subjects have intentionally been left out of this document. One is the Byzantine Fault Tolerant(BFT) protocol used by the validators to determine the next block of the masterchain or a shardchain; that subject is left for a forthcoming document dedicated to the TON Network. And although this document describes the precise format of TON Blockchain blocks, and discusses the blockchain's validity conditions and serialized invalidity proofs,<sup>[1](#fn1)</sup> it provides no details about the network protocols used to propagate these blocks, block candidates, collated blocks, and invalidity proofs.