1.
Gerardo Karel Boon. Economic choice human and physical factors in production. Amsterdam : North-Holland Publishing Company, 1964. 332 p. (Economic Analysis, 35)
2.
PAN-00008587 - coin/coin-related, Karel V (1506-1555), hollandse penning
PAN-00025437 - coin/coin-related, Karel V (1506-1555), hollandse penning
PAN-00032290 - coin/coin-related, Karel V (1506-1555), hollandse penning
PAN-00022164 - coin/coin-related, Karel V (1506-1555), hollandse penning
PAN-00045121 - coin/coin-related, Karel V (1506-1555), hollandse penning
PAN-00051542 - coin/coin-related, Karel V (1506-1555), hollandse penning
PAN-00048134 - coin/coin-related, Karel V (1506-1555), hollandse penning
PAN-00064124 - coin/coin-related, Karel V (1506-1555), hollandse penning