ArmstrongD. E.Performance as a function of expressed and nonexpressed levels of aspiration. Unpublished master's thesis, Harvard University, 1947.
2.
CrossonJ.The experimental analysis of vocational behavior in severely retarded males. Final report, Grant No. OEG 32-47-0230-6024. Washington, D.C.: Department of Health, Education and Welfare, 1967.
3.
BellamyT., & ChamberlainP.Vocational training for severely and moderately retarded adults. In Innovations: Models and remodels from the UAF's. Boston: Association of University Affiliated Facilities, 1974.
4.
BellamyT., PetersonL., & CloseD.Habilitation of the severely and profoundly retarded: Illustrations of competence. Education and Training of the Mentally Retarded, 1975, 10, 174–186.
5.
FryerF. W.An evaluation of level of aspiration as a training procedure. Englewood Cliffs, N.J.: Prentice-Hall, 1964.
6.
GordonS., O'ConnorN., & TizardJ.Some effects of incentives on the performance of imbeciles. British Journal of Psychology, 1954, 45, 277–287.
7.
HopkinsK. D., & GlassG. V.Basic statistics for the behavioral sciences. Englewood Cliffs, N.J.: Prentice-Hall, 1978.
8.
IrvinL. K.General utility of easy-to-hard discrimination training procedures. In BellamyT. (Ed.), Habilitation of the severely and profoundly retarded: Reports from the Specialized Training Program. Eugene, Oregon: University of Oregon Center on Human Development, 1976.
9.
IrvinL., & BellamyT.Manipulation of stimulus features in vocational skill training of the severely retarded: Relative efficacy. In BellamyT. (Ed.), Habilitation of the severely and profoundly retarded: Reports from the Specialized Training Program. Eugene, Oregon: University of Oregon Center on Human Development, 1976.
10.
KauslerD. H.Aspiration level as a determinant of performance. Journal of Personality, 1959, 27, 356–361.
11.
KliebhanJ.Effects of goal setting and modeling on job performance of retarded adolescents. American Journal of Mental Deficiency, 1967, 72, 220–226.
12.
LevyJ.Social reinforcement and knowledge of results as determinants of motor performance among EMR children. American Journal of Mental Deficiency, 1974, 78, 752–758.
13.
LindquistE. F.Design and analysis of experiments in psychology and education. Boston: Houghton Mifflin, 1953.
14.
LocketteR. E.The effects of levels of aspiration upon the learning of skills. Dissertation Abstracts, 1956, 16, 284. (Abstract)
15.
WarnerD. A., & de JungJ. E.Effects of goal setting upon learning in educable retardates. American Journal of Mental Deficiency, 1971, 75, 681–684.
16.
ZimmermanJ., OverpeckC., EisenbergH., & GarlickB.Operant conditioning in a sheltered workshop. Rehabilitation Literature, 1969, 30, 326–334.