Proper motions of stars in the zone catalogue of 20,843 stars, 1900 :
zones -40⁰ to -52⁰ derived from photographs taken at the Royal Observatory, Cape of Good Hope /
under the directions of H. Spencer Jones ... and J. Jackson.

APA Citation

Royal Observatory, C. of Good Hope., Jackson, J. (John)., Jones, H. Spencer (Harold Spencer). (1936). Proper motions of stars in the zone catalogue of 20,843 stars, 1900: zones -40⁰ to -52⁰ derived from photographs taken at the Royal Observatory, Cape of Good Hope. London: H.M. Stationery Off..

MLA Citation

Royal Observatory, Cape of Good Hope, J. (John) Jackson, and H. Spencer (Harold Spencer) Jones. Proper Motions of Stars In the Zone Catalogue of 20,843 Stars, 1900: Zones -40⁰ to -52⁰ Derived From Photographs Taken At the Royal Observatory, Cape of Good Hope. London: H.M. Stationery Off., 1936.