The SPIRITS Architecture. - Lev Slutsman; Igor Faynberg; Hui-Lan Lu; Mark Weissman (RFC, 2001)

Service in the Public Switched Telephone Network/Intelligent Network (PSTN/IN) Requesting InTernet Service (SPIRITS) Protocol Requirements. - Igor Faynberg; Jorge Gato; Hui-Lan Lu; Lev Slutsman (RFC, 2002)