diff --git a/libethereum/BlockChainSync.cpp b/libethereum/BlockChainSync.cpp
index 6b87ce904..c3ea67e22 100644
--- a/libethereum/BlockChainSync.cpp
+++ b/libethereum/BlockChainSync.cpp
@@ -508,7 +508,7 @@ bool PV60Sync::shouldGrabBlocks(EthereumPeer* _peer) const
 {
 	auto td = _peer->m_totalDifficulty;
 	auto lh = _peer->m_latestHash;
-	auto ctd =  host().chain().details().totalDifficulty;
+	auto ctd = host().chain().details().totalDifficulty;
 
 	if (m_syncingNeededBlocks.empty())
 		return false;
diff --git a/libethereum/BlockChainSync.h b/libethereum/BlockChainSync.h
index f47d946e3..18e8158e6 100644
--- a/libethereum/BlockChainSync.h
+++ b/libethereum/BlockChainSync.h
@@ -131,6 +131,70 @@ private:
  * @brief Syncrhonization over PV60. Selects a single peer and tries to downloading hashes from it. After hash downaload is complete
  * Syncs to peers and keeps up to date
  */
+
+/**
+ * Transitions:
+ *
+ * Idle->Hashes
+ * 		Triggered when:
+ * 			* A new peer appears that we can sync to
+ * 			* Transtition to Idle, there are peers we can sync to
+ * 		Effects:
+ * 			* Set chain sync  (m_syncingTotalDifficulty, m_syncingLatestHash, m_syncer)
+ * 			* Requests hashes from m_syncer
+ *
+ *  Hashes->Idle
+ * 		Triggered when:
+ * 			* Received too many hashes
+ * 			* Received 0 total hashes from m_syncer
+ * 			* m_syncer aborts
+ * 		Effects:
+ * 			In case of too many hashes sync is reset
+ *
+ *  Hashes->Blocks
+ * 		Triggered when:
+ * 			* Received known hash from m_syncer
+ * 			* Received 0 hashes from m_syncer and m_syncingTotalBlocks not empty
+ * 		Effects:
+ * 			* Set up download manager, clear m_syncingTotalBlocks. Set all peers to help with downloading if they can
+ *
+ *  Blocks->Idle
+ * 		Triggered when:
+ * 			* m_syncer aborts
+ * 			* m_syncer does not have required block
+ * 			* All blocks downloaded
+ * 			* Block qeueue is full with unknown blocks
+ * 		Effects:
+ * 			* Download manager is reset
+ *
+ *  Blocks->Waiting
+ * 		Triggered when:
+ * 			* Block queue is full with known blocks
+ * 		Effects:
+ * 			* Stop requesting blocks from peers
+ *
+ *  Waiting->Blocks
+ * 		Triggered when:
+ * 			* Block queue has space for new blocks
+ * 		Effects:
+ * 			* Continue requesting blocks from peers
+ *
+ *  Idle->NewBlocks
+ * 		Triggered when:
+ * 			* New block hashes arrive
+ * 		Effects:
+ * 			* Set up download manager, clear m_syncingTotalBlocks. Download blocks from a single peer. If downloaded blocks have unknown parents, set the peer to sync
+ *
+ *  NewBlocks->Idle
+ * 		Triggered when:
+ * 			* m_syncer aborts
+ * 			* m_syncer does not have required block
+ * 			* All new blocks downloaded
+ * 			* Block qeueue is full with unknown blocks
+ * 		Effects:
+ * 			* Download manager is reset
+ *
+ */
 class PV60Sync: public BlockChainSync
 {
 public:
@@ -204,9 +268,10 @@ private:
 
 	h256s m_syncingNeededBlocks;				///< The blocks that we should download from this peer.
 	h256 m_syncingLastReceivedHash;				///< Hash most recently received from peer.
-	h256 m_syncingLatestHash;					///< Peer's latest block's hash, as of the current sync.
-	u256 m_syncingTotalDifficulty;				///< Peer's latest block's total difficulty, as of the current sync.
-	EthereumPeer* m_syncer = nullptr;	// TODO: switch to weak_ptr
+	h256 m_syncingLatestHash;					///< Latest block's hash of the peer we are syncing to, as of the current sync.
+	u256 m_syncingTotalDifficulty;				///< Latest block's total difficulty of the peer we aresyncing to, as of the current sync.
+	// TODO: switch to weak_ptr
+	EthereumPeer* m_syncer = nullptr;			///< Current
 };
 }
 }