Page 2 to 6: Start Pages | Page 7: Ethmane Ould Oumar – Acknowledgments | Page 8 to 19: Ethmane Ould Oumar – Introduction | Page 20: Ethmane Ould Oumar – Presentation | Page 21 to 67: Ethmane Ould Oumar – Chapter 1. The theoretical foundations | Page 68 to 89: Ethmane Ould Oumar – Chapter 2. Fieldwork and methodology | Page 90: Ethmane Ould Oumar – Presentation | Page 91 to 129: Ethmane Ould Oumar – Chapter 3. Presentation of the results of the work | Page 130 to 161: Ethmane Ould Oumar – Chapter 4. Discussion of the results and attempt at conceptualization | Page 162: Ethmane Ould Oumar – Presentation | Page 163 to 182: Ethmane Ould Oumar – Chapter 5. So, What? Practical applications | Page 183 to 212: Ethmane Ould Oumar – Chapter 6. Managerial recommendations | Page 213 to 219: Ethmane Ould Oumar – Conclusion | Page 220 to 226: Bibliography | Page 227 to 228: End pages.