The Questions of the Naga King Sagara
The sutra known as The Questions of the Naga King Sagara (Skt. Sāgaranāgarājaparipṛcchā; Tib. ཀླུའི་རྒྱལ་པོ་རྒྱ་མཚོས་ཞུས་པ་, lü gyalpo gyatsö shyüpa, Wyl. klu’i rgyal po rgya mtshos zhus pa) is found in the General Sutra section of the Tibetan Kangyur (Toh 155).
In this very brief sutra, the Buddha explains the four seals of dharma to a naga king and assembly of monks.