The Canon Camera Museum has published a technical report on the Canon EF 24-70mm f/4L IS USM & EF 35mm f/2 IS USM lenes.
Purchase opportunities:
Canon EF 24-70mm f/4L IS USM Lens: B&H | Adorama | Amazon | BuyDig
Canon EF 35mm f/2 IS USM Lens: B&H | Adorama | Amazon