John W. Gowen
STUDIES IN MILK SECRETION. V. ON THE VARIATIONS AND CORRELATIONS OF MILK SECRETION WITH AGE
Genetics 1920 5: 111–188
[PDF]  

James P. Kelly
A GENETICAL STUDY OF FLOWER FORM AND FLOWER COLOR IN PHLOX DRUMMONDII
Genetics 1920 5: 189–248
[PDF]  

Edgar Altenburg and Hermann J. Muller
THE GENETIC BASIS OF TRUNCATE WING,—AN INCONSTANT AND MODIFIABLE CHARACTER IN DROSOPHILA
Genetics 1920 5: 248
[Abstract] [PDF]  

Don C. Warren
SPOTTING INHERITANCE IN DROSOPHILA BUSCKII COQ
Genetics 1920 5: 248
[Abstract] [PDF]