INTERSTELLAR EXTINCTION - CALIBRATION BY PLANETARY-NEBULAE

[11] ALLER LH, 1969, SKY TELESCOPE, V37, P348

[12] SPECTROPHOTOMETRIC STUDIES OF GASEOUS NEBULAE .8. IRREGULAR PLANETARY NEBULA NGC 2440 [J]. ASTROPHYSICAL JOURNAL, 1968, 151 (1P1) : 187 - &

[13] STRATIFICATION EFFECTS IN PLANETARY NEBULA NGC 7009 [J]. ASTROPHYSICAL JOURNAL, 1975, 197 (01) : 175 - 184

[14] ALLER LH, 1965, LANDOLT BORNSTEIN, V1, P573

[15] ALLER LH, 1964, GALAXY MAGELLANIC CL

[16] NEBULAR PHOTOMETRY WITH AN ECHELLE SPECTROMETER - [O-III] LINE RATIOS IN NGC-1976 AND NGC-6853 [J]. ASTROPHYSICAL JOURNAL, 1974, 188 (03) : 529 - 532

[17] CALCULATIONS OF LEVEL POPULATIONS FOR LOW LEVELS OF HYDROGENIC IONS IN GASEOUS NEBULAE [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1971, 153 (04) : 471 - +

[18] LINE SPECTRA OF HELIUM IN GASEOUS NEBULAE [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1972, 157 (02) : 211 - +

[19] DISTANCES AND DISTRIBUTION OF PLANETARY NEBULAE [J]. ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1971, 22 : 319 - &

[20] CAHN JH, 1973, ASTRON ASTROPHYS, V25, P477

[11] ALLER LH, 1969, SKY TELESCOPE, V37, P348

[12] SPECTROPHOTOMETRIC STUDIES OF GASEOUS NEBULAE .8. IRREGULAR PLANETARY NEBULA NGC 2440 [J]. ASTROPHYSICAL JOURNAL, 1968, 151 (1P1) : 187 - &

[13] STRATIFICATION EFFECTS IN PLANETARY NEBULA NGC 7009 [J]. ASTROPHYSICAL JOURNAL, 1975, 197 (01) : 175 - 184

[14] ALLER LH, 1965, LANDOLT BORNSTEIN, V1, P573

[15] ALLER LH, 1964, GALAXY MAGELLANIC CL

[16] NEBULAR PHOTOMETRY WITH AN ECHELLE SPECTROMETER - [O-III] LINE RATIOS IN NGC-1976 AND NGC-6853 [J]. ASTROPHYSICAL JOURNAL, 1974, 188 (03) : 529 - 532

[17] CALCULATIONS OF LEVEL POPULATIONS FOR LOW LEVELS OF HYDROGENIC IONS IN GASEOUS NEBULAE [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1971, 153 (04) : 471 - +

[18] LINE SPECTRA OF HELIUM IN GASEOUS NEBULAE [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1972, 157 (02) : 211 - +

[19] DISTANCES AND DISTRIBUTION OF PLANETARY NEBULAE [J]. ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1971, 22 : 319 - &

[20] CAHN JH, 1973, ASTRON ASTROPHYS, V25, P477