Click here for a pdf version of my publications or try Google Scholar.

Books and reports

Papers in refereed journals

Click here for a pdf version of my publications or try Google Scholar.

• Walther O, Amilhat Szary AL, Brambilla C, Brunet-Jailly E, Klatt M, Laine J, Moyo I, Nugent P, Ptak T, Radil S. 2023. Border studies at 45. Political Geography, online.
• Radil S, Walther O, Dorward N, Pflaum M. 2023. Urban-rural geographies of political violence in North and West Africa. Africa Security 16(1).
• Walther O, Prieto-Curiel R, Padron J, Scheuer J. 2023. Mapping the travel geography of the 9/11 network. The Professional Geographer (online).
• Ehrkamp P, Bennett M, Enns C, Grove K, Menga P, Vradis A, Walther O. 2023. Small steps. Political Geography 100, 102821.
• Walther O, Radil S, Russell D, Trémolières M. 2023. Introducing the Spatial Conflict Dynamics indicator of political violence. Terrorism and Political Violence 35(3): 533-552.
• Radil S, Irmisher I, Walther O. 2022. Contextualizing the relationship between borderlands and political violence: A dynamic space-time analysis in West and North Africa. Journal of Borderlands Studies 37(2): 253-271.
• Rojas J, Walther O. 2022. Revolutionary insurgents or conservative reactionaries? National Liberation Army’s transnational expansion in Colombia and Venezuela. Journal of Latin American Geography 22(2): 6-33.
• Walther O. 2022. Trade and security in African borderlands – An introduction. Journal of Borderlands Studies 37(2): 229-234.
• Walther O, Radil S, Russell D. 2021. Mapping the changing structure of conflict networks in North and West Africa. African Security 14(3): 211-238.
• Walther O, Klatt M, Boedeltje F. 2021. Mapping international co-authorship networks in border studies (1986-2018). Journal of Borderlands Studies 36(4): 653-674.
• Skillicorn D, Walther O, Leuprecht C, Zheng Q. 2021. The diffusion and permeability of political violence in North and West Africa. Terrorism and Political Violence 33(5): 1032-1054.
• Prieto Curiel R, Walther O, O’Clery C. 2020. Uncovering the internal structure of Boko Haram through its mobility patterns. Applied Network Science 5(28): 1-23.
• Valerio V, Walther O, Eilittä M, Cissé B, Kiker G, Muneepeerakul R. 2020. Network analysis of regional livestock trade in West Africa. PLoS ONE 15(5): e0232681.
• Walther O, Pedersen SP. 2020. Rebel fragmentation in Syria’s civil war. Small Wars & Insurgencies 31(3): 445-474.
• Walther O, Dambo L, Koné M. 2020. Urbanisation et villes frontalières en Afrique de l’Ouest. L’Information Géographique 85(2): 32-48.
• Walther O, Leuprecht C, Skillicorn D. 2020. Political fragmentation and alliances among armed non-state actors in North and Western Africa (1997-2014). Terrorism and Political Violence 32(1): 167-186.
• Walther O, Dambo L, Koné M, van Eupen M. 2019. Mapping travel time to assess accessibility in West Africa: The role of borders, checkpoints and road conditions. Journal of Transport Geography 82.
• Walther O, Tenikue M, Trémolières M. 2019. Economic performance, gender and social networks in West African food systems. World Development 124: 1-14.
• Walther O, Koné M. 2018. Commerce de réexportation des textiles et villes frontalières entre Niger et Nigéria. Cahiers d’Outre-Mer 278: 465-491.
• Leuprecht C. Walther O, Skillicorn D, Ryde-Collins H. 2017. Hezbollah’s global tentacles: A relational approach to convergence with transnational organised crime. Terrorism and Political Violence 29(5): 902-921.
• Leuprecht C, Aulthouse A, Walther O. 2016. The puzzling resilience of transnational organized criminal networks. Police Practice and Research 17(4): 376-387.
• Kuépié M, Tenikue M, Walther O. 2016. Social networks and small businesses performance in West African border regions. Oxford Development Studies 44(2): 202-219.
• Zheng Q, Skillicorn D, Walther O. 2015. Signed directed social network analysis applied to group conflict. IEEE International Conference on Data Mining Workshop (ICDMW): 1007-1014.
• Walther O, Christopoulos D. 2015. Islamic terrorism and the Malian rebellion. Terrorism and Political Violence 27(3): 497-519.
• Dörry S, Walther O. 2015. Contested relational policy spaces in two European border regions. Environment and Planning A 47(2): 338-355.
• Walther O. 2015. Business, brokers and borders: The structure of West African trade networks. Journal of Development Studies 51(5): 603-620.
• Walther O, Howard A, Retaillé D. 2015. West African spatial patterns of economic activities: combining the ‘spatial factor’ and ‘mobile space’ approaches. African Studies 74(3): 346-365.
• Walther O. 2014. Trade networks in West Africa: A social network approach. Journal of Modern African Studies 52(2): 179-203.
• Walther O, Christopoulos D. 2014. The 2012 Malian conflict network. Connections 34(1-2): 52-53.
• Dautel V, Walther O. 2014. The geography of innovation in a small metropolitan region: An intra-regional approach in Luxembourg. Papers in Regional Science 93(4): 703-726.
• Decoville A, Durand F, Sohn C, Walther O. 2013. Comparing cross-border metropolitan integration in Europe: Towards a functional typology. Journal of Borderlands Studies 28(2): 221-237.
• Walther O, Reitel B. 2013. Cross-border policy networks in the Basel region: the effect of national borders and brokerage roles. Space & Polity 17(2): 217-236.
• Retaillé D, Walther O. 2013. Conceptualizing the mobility of space through the Malian conflict. Annales de Géographie 6: 595-618.
• Walther O. 2012. Traders, agricultural entrepreneurs and the development of cross-border regions in West Africa. Entrepreneurship and Regional Development 24(3-4): 123-141.
• Walther O. 2012. Sons of the soil and conquerors who came on foot: The historical evolution of a West African border region. African Studies Quarterly 13(1-2): 75-92.
• Walther O, Schulz C, Dörry S. 2011. Specialized international financial centres and their crisis resilience: the case of Luxembourg. Geographische Zeitschrift 99(2-3): 123-142.
• Retaillé D, Walther O. 2011. Spaces of uncertainty: a model of mobile space in the Sahel. Singapore Journal of Tropical Geography 32(1): 85-101.
• Walther O, Dautel V. 2010. Intra-regional employment growth in Luxembourg (1994-2005). Geografiska Annaler: Series B, Human Geography 92(1): 45-63.
• Walther O, Schulz C. 2009. Finanzplatz Luxemburg–vom ‘Steuerparadies‘ zur Investmentfonds-Kapitale. Geographische Rundschau 61(1): 30-35.
• Sohn C, Reitel B, Walther O. 2009. Cross-border metropolitan integration in Europe: the case of Luxembourg, Basel and Geneva. Environment and Planning C: Government and Policy 27: 922-939.
• Walther O. 2009. A mobile idea of space. Traders, patrons and the cross-border economy in Sahelian Africa. Journal of Borderlands Studies 24(1): 34-46.
• Walther O, Retaillé D. 2008. Le modèle sahélien de la circulation, de la mobilité et de l’incertitude spatiale. Autrepart 47: 109-124.

Book chapters

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• Walther O, Retaillé D. 2021. Mapping the Sahelian space, in Villalon L (ed.) The Oxford Handbook of the African Sahel. Oxford, Oxford University Press: 15-34.
• Leuprecht C, Walther O. 2018. Applying social network analysis to terrorist financing, in Walker, King, Gurule (eds) The Palgrave Handbook on Criminal and Terrorism Financing Law. Basingstoke, Palgrave MacMillan: 945-966.
• Walther O, Leuprecht C, Skillicorn D. 2018. Networks and spatial patterns of extremist organizations in North and West Africa, in Walther O, Miles W. (eds). African Border Disorders. Abingdon, Routledge: 60-86.
• Skillicorn D, Walther O, Zheng Q, Leuprecht C. 2018. Spatial and temporal diffusion of political violence in North and West Africa, in Walther O, Miles W. (eds). African Border Disorders. Abingdon, Routledge: 87-112.
• Walther O. 2017. Regional integration, in Binns T, Lynch K, Nel E (eds) The Routledge Handbook of African Development. London, Routledge: 286-299.
• Walther O, Retaillé D. 2015. Rethinking borders in a mobile world: An alternative model, in Amilhat-Szary A.-L, Giraut F. (eds) Borderities and the Politics of Contemporary Mobile Borders. Basingstoke, Palgrave Macmillan: 191-203.
• Walther O. 2015. Niger-Benin: The Niger-Mekrou Rivers and the Lété Island, in Brunet-Jailly E (ed.) Border Disputes: A Global Encyclopaedia. Santa Barbara, ABC-CLIO: 694-704.
• Decoville A, Durand F, Sohn C, Walther O. 2014. Approche comparée de l’intégration métropolitaine transfrontalière en Europe, in Beck J, Wassenberg B (eds) Vivre et Penser la Coopération Transfrontalière (vol. 6). Stuttgart, Franz Steiner: 175-194.
• Walther O. 2014. Borders, cross-border co-operation and freedom of movement in the Sahara-Sahel (chap. 7) and Security issues, movement and networks in the Sahara-Sahel (chap.8), in SWAC/OECD (ed.) An Atlas of the Sahara-Sahel: Geography, Economics and Security. Paris, OECD: 155-172, 173-224.
• Walther O. 2014. La construction historique de la région frontalière du Dendi (Afrique de l’Ouest), in Amadou B, Dambo L. (eds) Sahel: Entre Crises et Espoirs. Paris, L’Harmattan: 89-108.
• Retaillé D, Walther O. 2014. Space and mobility: Lessons from the Sahel to the globalized world, in Boesen E, Marfaings L (eds) Mobilité dans l’Espace Ouest-Africain: Ressources, Développement Local et Intégration Régionale. Paris, Karthala: 207-234.
• Walther O. 2012. Regional growth of the knowledge economy in Luxembourg, in Sohn C. (ed.) Luxembourg: An Emerging Cross-Border Metropolitan Region. Brussels: Peter Lang: 41-63.
• Walther O, Schulz C. 2012. Financial services clustering in Luxembourg-City, in Sohn C. (ed.) Luxembourg: An Emerging Cross-Border Metropolitan Region. Brussels: Peter Lang: 65-90.
• Walther O. 2012. Metropolitan regions and cross-border demographic integration, in Sohn C. (ed.) Luxembourg: An Emerging Cross-Border Metropolitan Region. Brussels: Peter Lang: 185-204.
• Sohn C, Walther O. 2012. Building a cross-border metropolitan region: the political stakes of scalar restructuring, in Sohn C. (ed.) Luxembourg: An Emerging Cross-Border Metropolitan Region. Brussels: Peter Lang: 265-278.
• Walther O. 2010. Economie et frontières en Afrique sahélienne: un usage clientéliste de la partition coloniale, in Igué JO, Fodouop K, Aloko-N’Guessan J. (eds) Maîtrise de l’Espace et Développement en Afrique. Etat des Lieux. Paris: Karthala: 125-137.
• Schulz C, Walther O. 2009. Finanzplatz Luxemburg, in Bousch P. et al. (eds) Atlas du Luxembourg. Cologne: Emons: 130-133.
• Dautel V, Walther O. 2009. Beschäftigungsdynamik in der Metropolregion, in Bousch P. et al. (eds) Atlas du Luxembourg. Cologne: Emons: 128-129.
• Racine J.-B, Walther O. 2007. Geografia de las religiones, in Hiernaux D, Lindon A. (eds) Tratado de Geografia Humana. Barcelona: Anthropos: 481-505.
• Walther O. 2005. “Merci patron…”. L’espérance de recevoir et l’obligation d’offrir dans les relations clientélistes au Niger et au Bénin, in Reynard E, Dambo L. (eds) Vivre dans les Milieux Fragiles. Lausanne: Institute of Geography: 60-75.

Other publications

Click here for a pdf version of my publications or try Google Scholar.

• Walther O, Prieto Curiel R, Padron J, Scheuer J. 2022. Mapping the travel geography of the 9/11 terrorist network. SSRN 4206577.
• Walther O, Prieto Curiel R, Padron J, Scheuer J. 2022. Geography Lessons From the 9/11 Terrorist Network. Lawfare, 6 Sep.
• Rojas J, Walther O. 2022. As Colombia Resumes Negotiations with the ELN, the Path Towards Peace Lies through Venezuela. NACLA, 1 Dec.
• Radil S, Walther O, Dorward N, Pflaum M. 2022. Urban-rural geographies of political violence in North and West Africa. SSRN 4171240.
• Radil S, Walther O, Dorward N, Pflaum M, Trémolières M. 2022. Conflicts are becoming increasingly rural in North and West Africa. OECD Development Matters, 26 July.
• Walther O, Radil S, Russell D, Trémolières M. 2020. Introducing the Spatial Conflict Dynamics indicator of political violence. arXiv 2003.01750.Walther O. 2020. Femmes et conflicts en Afrique de l’Ouest. OECD West African Papers 28.
• Walther O, Radil S, Russell D. 2019. Mapping the geography of political violence in North and West Africa. OECD Development Matters, 17 Oct.
• Walther O. 2019. Frontières, sécurité et développement en Afrique de l’Ouest. OECD West African Papers 26.
• Walther O. 2019. Comment on African Borders: Putting Paid to a Myth. Journal of Borderlands Studies (read).
• Trémolières M, Walther O. 2019. Accessibility and infrastructure in border cities. OECD West African Papers 23.
• Trémolières M, Walther O. 2019. Business and health in border cities. OECD West African Papers 22.
• Trémolières M, Walther O. 2019. Population and morphology of border cities. OECD West African Papers 21.
• Trémolières M, Walther O. 2019. Regional integration in border cities. OECD West African Papers 20.
• Radil S, Walther O. 2018. Social networks and geography: a view from the periphery. arXiv 1805.04510.
• Hoffmann L, Melly P, Walther O. 2017. Empowering Women in West African Markets. Case Studies from Kano, Katsina (Nigeria) and Maradi (Niger). Dakar, World Food Programme (download).
• Walther O. 2017. The blurred boundaries of political violence in the Sahel-Sahara. OECD Development Matters, 29 September (read).
• Walther O. 2017. Wars and conflicts in the Sahara-Sahel. OECD West African Papers 10.
• Walther O, Renk S. 2017. Can social network analysis inform African development policies? Dakar, World Food Programme (download).
• Walther O. 2017. Cross-border co-operation networks in West Africa. Paris, OECD West African Papers 6.
• Walther O, Kuépié M, Tenikue M. 2017. When social networks become a burden for African traders. Washington DC, The Brookings Institution, Africa in Focus Series (read).
• Walther O. 2016. Mapping West African Trade Networks. Washington DC, The Brookings Institution, Africa in Focus Series (read).
• Walther O, Leuprecht C, Skillicorn D. 2016. Wars Without Beginning or End: Violent Political Organizations and Irregular Warfare in the Sahel-Sahara. arXiv  (download).
• Skillicorn D, Walther O, Zheng Q, Leuprecht C. 2016. Distance, Borders, and Time: The Diffusion and Permeability of Political Violence in North and West Africa. arXiv (download).
• Walther O, Tisseron A. 2015. Strange bedfellows: a network analysis of Mali’s northern conflict. The Broker (read).
• Walther O. 2015. Eating soup with a knife: Confronting warfare in the Sahara. OECD Observer 303.
• Walther O, Vollmer S. 2015. Mapping the potential of cross-border cooperation in West Africa. GREAT Insights 4(6): 34-36.
• Carpentier S, Dörry S, Lord S, Matthey L, Nelles J, Walther O. 2015. Navigating the heavy seas of online publishing: Reflections on ten years editorship. Journal of Urban Research (read).
• Walther O, Leuprecht C. 2015. Mapping and deterring violent extremist networks in North-West Africa. Sønderborg, Department of Border Region Studies Working Papers 4.
• Walther O. 2015. Social Network Analysis and informal trade. Sønderborg, Department of Border Region Studies Working Papers 1.
• Walther O. 2014. Border markets: An introduction. Journal of Urban Research 10.
• Retaillé D, Walther O. 2013. L’actualité sahélo-saharienne au Mali: une invitation à penser l’espace mobile. Annales de Géographie 694(6): 595-618.
• Hamez G, Amilhat-Szary A.-L, Paris D, Reitel B, Walther O. 2013. Guest editorial: Modelling and benchmarking of borders. Belgeo 1.
• Walther O, Tenikue M, Kuepié M. 2012. Regional trade and border markets between Niger, Benin and Nigeria. Luxembourg: CEPS/INSTEAD Technical Papers (read).
• Nelles J, Walther O. 2011. Changing European borders: from separation to interface? An introduction.  Journal of Urban Research 6.
• Retaillé D, Walther O. 2011. Guerre et terrorisme au Sahara-Sahel: la reconversion des savoirs nomades. L’Information Géographique 76(3): 51-68.
• ESPON. 2010. METROBORDER. Cross-border Polycentric Metropolitan Regions. Final Report. Luxembourg, European Spatial Planning Observation Network (download).
• Schaber C, Walther O. 2010. Tourism in the Hombori region (Mali). Neuchâtel: Hombori Biodiversity Monitoring Project, Mission (read).
• Walther O, Retaillé D. 2010. Sahara or Sahel? The fuzzy geography of terrorism in West Africa. Luxembourg: CEPS/INSTEAD Working Papers 35.
• Dautel V, Walther O. 2009. Croissance de l’emploi et mobilité des entreprises au Luxembourg. Luxembourg: CEPS/INSTEAD Population & Territoire 15.
• Sohn C, Walther O. 2008. Géographie des activités économiques métropolitaines au Luxembourg. Luxembourg: CEPS/INSTEAD Population & Territoire 14.
• Walther O, Renaud T, Kissling J. 2008. Heaven on Earth? The development of tourism in the Dogon Country and the Hombori Mountains (Mali). Journal of Urban Research 4.
• Beek W van, Lemineur P, Walther O. 2007. Tourisme et patrimoine au Mali. Destruction des valeurs anciennes ou valorisation concertée? Geographica Helvetica 4: 249-258.
• Walther O. 2007. Villes-frontières et réseaux informels sahéliens (Gaya-Malanville-Kamba). Geographica Helvetica 1: 10-20.
• Walther O. 2007. L’échange généralisé: urbanisation et relations villes-campagnes en Afrique de l’Ouest. Paris: Sahel and West Africa Club (read).
• Walther O. 2006. Le développement touristique dans les Monts Hombori (Mali). Neuchâtel: Hombori Biodiversity Monitoring Project, Mission Report (read).
• Walther O. 2004. Au-delà de l’opposition entre villes et campagnes. Esquisse d’un modèle territorial dynamique en Afrique de l’Ouest. L’Information Géographique 68: 308-319.
• Racine J.-B, Walther O. 2003. Géographie et religions. Une approche territoriale du religieux et du sacré. L’Information Géographique 66: 193-221.

Book reviews

• African Interventions, by E. Kisangani and J. Pickering, African Studies Quarterly (read).
• Mobility, Mobilization, and Counter/Insurgency, by D. Agbiboa, Space and Polity (read).
• Boundaries, communities and state-making in West Africa, by P. Nugent, Journal of Borderlands Studies (read).
• Foreign Intervention in Africa After the Cold War, by E. Schmidt. African Studies Quarterly (read).
• A History of Borno, by V. Hiribarren, African Studies Quarterly (read).
• The Edge of the World, by M. Pye, Journal of Borderlands Studies (read).
• Regionalism in Africa, by D. Bach, Journal of Borderlands Studies (read).
• Contemporary Regional Development in Africa, by K.T. Hanson, Journal of Urban Research (read).
• Land, Mobility, and Belonging in West Africa, by C. Lentz, Journal of African History (read).
• Les Lieux de la Mondialisation, by D. Retaillé, Journal of Urban Research (read).
• Bordering and Ordering the Twenty-First Century, by G. Popescu, Journal of Urban Research (read).
• Triumph of the City, by E. Glaeser, Journal of Urban Research (read).
• London. The Biography, by P. Ackroyd. Journal of Urban Research (read).
• Reshaping Economic Geography, by The World Bank, Cybergeo: European Journal of Geography (read).

Links to PDFs in OA journals, where available; otherwise, PDFs are intended for single copy, research use only, to comply with copyright regulations.