1. Alexandre, P., Ngounou, Y., Doroftei, I., Preumont, A., 1996. A conceptual walking vehicle for planetary exploration. Fourth ESA Workshop on Advanced Space Technologies for Robot Applications—ASTRA 96, ESTEC, Noordwijk.
2. Alvarez, A.M., 1990. A 4-legged walking robot for mars exploration, Doc. Ref. WAT/TN/AMA/241195.
3. Alvarez, A.M., de Peuter, W., Gonzalez de Santos, P., Armada, M., 1994. A survey of locomotion concepts for planetary exploration rovers. 3rd ESA Workshop on Advances in Space Technology for Robot Applications—ASTRA 94, ESTEC, Noordwijk.
4. WALKIE 6-A walking demonstrator for planetary exploration;Amati;Space For.,2000
5. Three rigid frames walking planetary rovers;Amati;Acta Astron.,2002