Additional info obtained from:

• Корабли ВМФ СССР. Многоцелевые ПЛ и ПЛ спецназначания (roughly: "Ships of the USSR - Multirole-Submarines and Specialpurpose-Submarines"), Y. Apalkov, Saint Petersburg, 2003, ISBN 5-8172-0069-4
• Подводные лодки Росси (roughly : "Russian Submarines"), W. Ilyin, A. Kolesnikov, Moscow AST, 2006, ISBN 5-17-037644-8
• Подводный щит СССР - Атомные многоцелевые подводные лодки (roughly : "Underwatershield of the USSR - Multirole Nuclear Submarines"), Part 1, Vladimir Demyan, Alexander Kotlobovski, Major publishing house, 2003
• Russian Submarines: Guardians of the Motherland, Wayne Frey, 2006, ISBN 978-0741434470

Information, regarding specific details of construction, were found in some russian infotainment programs, like:

• Ударная сила. Подводный охотник (roughly : "Impact force. Spearfishers" as aired by russian "Channel One" television channel.)
• Военное дело - Атомный гепард (roughly : "Military. Atomic Cheetah" as aired by russian "NTV" television channel.)