English
iGCSE Revision booklet
https://www.wadebridge.cornwall.sch.uk/assets/file/iGCSE%20Revision%20booklet%201.pdf
Chemistry
https://www.smartexamresources.com/igcse-chemistry-study-notes
Physics
https://mrtremblaycambridge.weebly.com/uploads/9/7/8/8/9788395/physics-igcse.pdf
Computer science
https://www.savemyexams.com/igcse/