“…1977; Soliman & Laberge 1978; Spoerel et al. 1978; Ungerer 1978; Byrick 1980; Spoerel 1980, 1981, 1983; Humphrey 1982; Stenqvist & Sonander 1984), the modified version soon became popular in human and veterinary anaesthesia (Chu et al. 1977; Fryer 1978; Hird & Carlucci 1978a,b; Soliman & Laberge 1978; Manley & McDonell 1979a,b; Cullen 1989) particularly in cases where head access was limited.…”