"Tibet : a geographical, ethnographical, and historical sketch derived from Chinese sources" by W. Woodville Rockhill. From the "Journal of the Royal Asiatic Society of Great Britain and Ireland " [1891].
Rockhill's Plan of Lhasa was published in "Tibet : a geographical, ethnographical, and historical sketch" by William Woodville Rockhill in 1902. William Woodville Rockhill was an American diplomat and scholar, who traveled extensively in China and Tibet. In his travels, Rockhill was unable to reach Lhasa; his plan was drawn from Chinese sources. Mongolian Buddhist lamas, G. Ts. Tsybikoff [Tsybikov] and Ovshe (O. M.) Norzunoff [Norzunov] were familiar with the plan and mentioned it in their notes (available in this digital collection at: http://collections.lib.uwm.edu/u?/tibet,106 ) that accompany a set of 50 photographs of Lhasa taken in 1900-1901.