PCOD= PCOD, pulp × CODgewogen referentie, pulp/(CODgewogen referentie, pulp + CODreferentie, papier) + PCOD, papier × CODreferentie, papier/(CODgewogen referentie, pulp + CODreferentie, papier).
PCOD= PCOD, pulp × CODweighted reference, pulp/(CODweighted reference, pulp + CODreference, paper) +PCOD, paper × CODreference, paper/(CODweighted reference, pulp + CODreference, paper)