BN Cat. gén. : Pierson (Nikolaas Gerard)
Internet : http://www.lincei.it (Elenco generale dei soci dell'Accademia dal 1870),
1999-04-29
Leerboek der staathuishoudkunde / door Nikolaas Gerard Pierson, 1896-1902. Collectivist
economic planning / by Nikolaas Gerard Pierson [et al.], 1975