lookup data

Hello,

trying to make this work:

In sheet A, i have 

 Column A: Start Date

 Column B: End Date

 Column C: Article A costprice

 Column 😧 Article B costprice

 Column E - T: Article C to Article R costprice

Every month, costprice changes (not for every article), so i adapt this manually in the correct Article Column.

In my Sheet B, i try to calculate the costprice per order/article.

I use nested IF functions to look for return value in column F, but this gets out of hand.

=IF(C2='kostprijs pallet'!$C$1;VLOOKUP(A2;'kostprijs pallet'!A:T;3);IF(C2='kostprijs pallet'!$D$1;VLOOKUP(A2;'kostprijs pallet'!A:T;4);IF(C2='kostprijs pallet'!$E$1;VLOOKUP(A2;'kostprijs pallet'!A:T;5);IF(C2='kostprijs pallet'!$F$...

* 'kostprijs pallet' = sheet A

Is there a formula i can use? One that looks in the correct period of time (delivery time) and selects the correct article?