Football Swap Cards.
The fronts of the cards had the pictures while the backs (in various colours) included the instructions. You obtained tokens which appeared every day in the Sun during the 1970/71 football season and send them away to receive some swap cards.
The cards were to be mounted in the spaces left for them in the 164-page Scrapbook Encyclopaedia of Football.
Information from Nigel's Webspace
The Sun 'Soccer Stickers 1989 / 90'.
I have these 4 stickers.