008981127s1975 us a 001a eng ■041 ▼aeng ■090 ▼a545.1▼bF533w ■1001 ▼aFisher, Robert ■24510▼aWalls▼dby Robert Fisher ■260 ▼aLondon▼bThe Macmillan Press Ltd.▼c1975 ■300 ▼aviii, 120p.▼bill▼c23cm ■50000▼aIncludes appendix and index ■504 ▼aReferences : p.114