[825] Heber Howe 1913.
[826] Knowles 1913.
[827] West, W. 1905.
[828] Lettau 1914.
[829] Lettau 1914.
[830] Parietin differs chemically from chrysophanic acid of Rheum, etc.
[831] Stenhouse and Groves 1877.
[832] Volkard 1894.
[833] Nylander 1866.
[834] Jumelle 1892.