WIA GC/1910/160 | Eijkman, Pieter Hendrik and Horrix, Paul to Warburg, Aby 06/05/1910 | their office collects data on international projects of every description; they invite Warburg to... |
WIA GC/1910/161 | Warburg, Aby to Eijkman, Pieter Hendrik and Horrix, Paul 10/05/1910 | since the organisation has changed its byelaws and the new version has not yet appeared in print... |
WIA GC/1910/162 | Eijkman, Pieter Hendrik and Horrix, Paul to Warburg, Aby 13/05/1910 | acknowledge receipt of his letter |