Some sentences from the booklet within the pc game 'Peter Pan', an old retro game. 

Part 4 of Arondil's Journal.

Yngvild Throne Room, on a table in Arondil's bedchamber beyond the throne room.

Part 3 of Arondil's Journal.

Yngvild caves. This one is a little bit easier to find. All you have to do is continue down from book 2 and before you enter Yngvild Throne Room look to the left and you will see a table where book 3 is located.

A journal written by a Adventurer. 

This book seems to coincide with the Merchant's Journal, both of which talk about the caravan attacks and lead the player to Chillwind Depths.

Found next to the corpse of Stromm in the Nchuand-Zel Quarters.

Stromm was a Breton conjurer and a scholar studying the Dwemer. His corpse can be found inside the Nchuand-Zel Quarters. His diary lies next to him. He went inside with Erj, Krag and Staubin but all have been killed by Falmer.

According to his diary, he "stayed behind with a guard to further study the living quarters."[1] The guard can be located slightly before the torture chamber in Nchuand-Zel.

The smuggler records his dismay at the cargo he's been smuggling.

The author is a smuggler.

Found inside Alftand Glacial Ruins on a table just after passing J'darr and the corpse of his brother J'zhar.

Umana is a Redguard and one of the explorers in the Alftand expedition.[1] She and Sulla Trebatius are encountered just before one of the many entrances into Blackreach. Both of them are hostile to the Dragonborn.

Sulla Trebatius is an Imperial Spellsword who can be found inside the Alftand Cathedral right above the entrance to Blackreach.

Japhet's Folly – Behind a locked door, in the basement, on a table next to Japhet's body.

Japhet was a warrior whose corpse can be found in the cellar of Japhet's Folly. The cellar can be found behind an expert locked door at the bottom of the main tower. The room is full of spider webs. The Dragonborn can find Japhet's Journal, a leveled sword and a master-locked chest next to his corpse.

He was the son of a farmer, and set out with a small company of men from Dawnstar to create a fortress which is now Japhet's Folly. The locals believed the island was haunted. Eventually, his followers left him one by one, but he refused to give up. He eventually died in the cellar, convinced that the rumors about Japhet's Folly being haunted were true.

Author of this Journal is Oronrel.