5-6/2023: [https://www.e-periodica.ch/digbib/view?pid=geo-007%3A2023%3A121%3A%3A96#96]
5-6/2022: [https://www.e-periodica.ch/digbib/view?pid=geo-007%3A2022%3A120%3A%3A96#96]
5-6/2021: [https://www.e-periodica.ch/digbib/view?pid=geo-007%3A2021%3A119%3A%3A96#108]
5/2020: [(https://www.e-periodica.ch/digbib/view?pid=geo-007%3A2020%3A118%3A%3A132#132)]
5/2019, 5/2018 usw.