Lóng hǔ huán dān jué 龍虎還丹訣

Instructions on the Dragon-Tiger Return-Elixir

by 李真人 (Lǐ zhēn rén) — Northern-Sòng pseudonymous Daoist

Northern-Sòng nèi dān instruction-text attributed to “Perfected Lǐ”. Preserved as DZ 1084 / CT 1084 (Tài xuán bù 太玄部).

Dating. Northern Sòng. Dynasty: 北宋.