00677nam a2200205Ia 4500 IN-BaIIA 211028s9999 xx 000 0 eng d IIA Library 521.97 CHA Chandler, S. C. 820 The science observer code, explanation of the number code pt.1-3 S. C. Chandler and J. Ritchie Boston Scientific Society 1888 17p. Occasional publication; no. 1 Astronomy and Astrophysics Thesaurus Observer Codes 821 Observing Techniques 822 Ritchie, J. 823 BK 375 375 0 0 0 0 BAN KOD GEN 0000-00-00 0 521.97/ CHA 368 2021-11-05 0000-00-00 BK