%0 Journal Article %K Health Policy %K Operational Research %B Health Policy and Planning %D 2020 %G eng %I Oxford University Press (OUP) %N Supplement_2 %P ii137-ii149 %R 10.1093/heapol/czaa123 %T Guiding principles for quality, ethical standards and ongoing learning in implementation research: multicountry learnings from participatory action research to strengthen health systems %U https://academic.oup.com/heapol/article-pdf/35/Supplement_2/ii137/38890969/czaa123.pdf %V 35