The 10c stamp is about Protection of blind with blind man's stick. A white cane is used by many people who are blind or visually impaired. Its primary uses are as a mobility tool and as a courtesy to others, but there are at least five varieties, each serving a slightly different need.
The 20c stamp shows the flags of EFTA MEMBERS. The European Free Trade Association (EFTA) is a free trade organisation between four European countries that operates in parallel with – and is linked to – the European Union (EU). The EFTA was established on 3 May 1960 as a trade bloc-alternative for European states who were either unable or unwilling to join the then-European Economic Community (EEC) which has now become the EU. The Stockholm Convention, establishing the EFTA, was signed on 4 January 1960 in the Swedish capital by seven countries (known as the "outer seven"). Today's EFTA members are Iceland, Liechtenstein, Norway, and Switzerland, of which the latter two were founding members. The initial Stockholm Convention was superseded by the Vaduz Convention, which enabled greater liberalisation of trade among the member states.
And, the 30c stamp is in the EUROPA CEPT series for 1967 showing the Cogwheels with CEPT badge.
Thank you Maria.