This diagram can be purchased from most armorers, including: * the Armorer in Kaer Trolde keep * the Armorer in Kaer Muire * the Armorer in Midcopse * the Armorer in Oxenfurt * Fergus Graem * Willis * Yoana * the Merchant at the Ard Skellig sawmill One copy of this diagram can be found in a submerged chest east of the bridge by Crippled Kate's brothel.